Why would a PC lock up?

Answer 1

Usually a PC locks up due to hardware or software conflicts. You can tell if it's a hardware conflict if the lock ups occur while using the same combination of equipment (e.g. printing while downloading something off the web). This was more common in older systems - but I haven't experienced this problem with newer PCs in the past few years due to their achievements in making equipment compatible with other vendors.

More commonly, a lockup is due to software conflicts. These are harder to troubleshoot, since they could appear randomly. Most times, this is due to a lack of memory. If you have a lot of software on your PC, they could be using most of your free memory. If you're running 128Mb or 256Mb with a Windows 2000 or greater OS, then you're probably lacking in RAM.

In the Task Manager, check out the Performance tab & peep the memory section (the 2nd graph Page File Usage History). If the yellow line is anywhere near 1/2 way through the grid, you might want to upgrade your memory or uninstall memory-hungry apps.

With today's prices, upgrading RAM is quite affordable. As for uninstalling unnecessary application, go to Control Panel & then to "Add/Remove Programs". Search for any unrecognized and unnecessary apps & remove them.

A computer may lock up when the hard drive is fragmented or almost full, and the registry is full of junk from previously installed programs. See related questions for advice on cleaning up.

If your PC doesn't give you any messages and screen is frozen, it might be hardware conflict or heat, but if your mouse still moves then I would check my video card, update drivers and check the temperatures.

Also, viruses and adware contribute to instability. So if you have tried nearly everything else, run some spyware and virus scanners. Back when Windows 98 was popular, some people complained of a green dot in the upper left corner of the screen and instability. That was spyware that did that. Removing the spyware made the dot disappear and the system lock up less.

If all else fails, it is probably the motherboard. Motherboards contain electrolytic capacitors which serve to filter the current (among other roles). With time, they may swell, leak, or explode. There are places which will replace them for you. Also, motherboards can develop broken traces and loose connections. In some cases, the problem is the ROM BIOS, and you can often flash it with a newer version that makes it more stable.

Answer 2

Most common cause would probably be a computer virus, but it can also be fault of hardware - for example fans are not spinning, and thus computer shuts down when processor or graphics card is overheated.

Answer 3

Your lock up issue may be an issue of lack of maintenance. Close all programs and email you have running. To check this out, first go to Start>Programs>Accessories>System Tools>Disk Cleanup. Check mark everything - no harm will come to your programs - and let the program run. When it is finished, shutdown (not restart) your computer. Second, clear your internet history (IE, Firefox). To do this, select History from the toolbar and then Clear Recent History.

These steps usually fix the problem, but if it is still with you, check on your available memory on your computer. To do this, go to My Computer or click on the yellow filefolder on your taskbar. Right click the icon for drive C and then select Properties from the menu. If you have very little available space (pink), then you have possibly loaded more applications (current MS Office, for example) or more files than the computer can hold and be able to also launch programs and run them. To fix this, you should remove some of the files, and/or revert to an older MS Office (for example) to create space. You might COPY some of these files to an external drive (really cheap for lots of space), check that they are ok and then remove them from the C drive. Then run the disk defragmenter (same place as disk cleanup). This may take awhile, so check in periodically to be sure that your screen saver hasn't come up. Doing this will create more disk space by making all files contiguous on your drive. For these last steps, you might try to hire a professional if you do not have a proficient teen in your household.

Answer 4

Lockups can be difficult to diagnose. They can be caused by both hardware and software problems. One of them most important clues you need to examine is when exactly it freezes. Here are the places it may freeze and what it may mean.

1. At random - This would be during boot sometimes, sometimes as the operating system loads, sometimes when you get a desktop, and sometimes during loading programs. That can be a problem with the memory, the BIOS, or the motherboard. You can try different memory sticks or remove one at a time to see if that stops the problem.

You can also go to your manufacturer's site and see if there is a newer BIOS/firmware version for your exact board than the version that is reported at boot. Or you can use a tool such as Belarc Advisor to find what version you have. Flashing a newer BIOS is only recommended if you are having problems, performance issues, or want to use hardware which your current version does not support. It is a delicate process, so you have to make sure it is not interrupted and that you don't lose power to the computer. Before you download a newer BIOS, you should check the change logs since your version to see if any of the newer versions address your problem. For instance, if it says it fixes "timing issues" or improves "system stability," then you probably should try it.

If you still have random lockups after changing the memory and upgrading the BIOS if possible, then you likely have a motherboard that is showing early signs of failure. In some situations, you can get the board refurbished. You can look for exploded, bulging or leaking electrolytic capacitors on the motherboard. Electrolytic capacitors look like tiny "cans." You can usually tell if any are bulging, leaking, or have the vents blown at the top. If you find that, you can likely send your board off to someone who can replace all the main capacitors.

2. Early in the boot process - The computer may not even POST. This is caused by a hardware problem. It could be the motherboard or a peripheral card such as the video card. In some cases, it could be a power supply problem. It could mean a problem with the BIOS/EFI such as a bad flashing process from a BIOS/firmware update. Or it could be something as simple as a BIOS switch on the motherboard being caught between settings.

3. Later in the boot process, but before reading the hard drive - This could be a power supply problem, even something as simple as having the wrong voltage selected on the back of the power supply. Or it could be a problem with the BIOS or motherboard.

4. When the system first tries to read the hard drive or start the OS - This could be due to a bad or failing hard drive, or it could even be a loose hard drive plug. In some cases, it could be due to a corrupt boot record on the hard drive or some bad system files.

5. In the middle of the Windows boot process - While this could be a hardware problem, it is more likely due to bad operating system files, a failing hard drive, or a bad system driver. You could try your hard drive manufacturer's test tool to see if the drive is failing. If it is, you could try to use spare sectors if the tool will let you and you don't have many errors. And then you'd want to back it up immediately and save what you can.

If you just installed a new device or driver, then you might want to try removing the device or rolling back the driver.

You might try to hit F8 on boot and attempt to run the last known good configuration. Or you can see if safe mode helps the problem.

You can try a repair install of your OS if the above steps don't help. Or alternately, you can scan for malware if you can sometimes get far enough to do so.

6. Right after the background is drawn but before Explorer loads - This could be a Windows problem. You could have an invalid entry in one of the autorun locations. Or it could be due to Windows file corruption. You could try a repair install of Windows.

7. When launching a program - This could be the fault of the program itself or a library needed to run that program. Or it could be a memory problem. Or the file could be on a bad sector.

8. When starting a video, movie, or game - This could be due to a bad video card, bad video driver, or bad codec. The codecs are the easiest to fix. You could download a trusted codec set such as KLite. When you install it, it will scan for codec-related problems.

If the problem persists, then try a newer version of the video card's driver if it exists. But if you just updated it and the problem started, then roll back the driver.

If nothing else, try a different video card.

9. When attempting to play music or audio - This could be a bad sound device, bad sound driver, or an audio codec problem. The steps are similar to section #8 above. You might want to try a good codec set first and see if that fixes the problem.

Then go to the audio device's manufacturer (or the motherboard manufacturer if you are using one on the motherboard), and download the latest version of the driver that is compatible with your operating system.

If the problem persists, you might want to replace the sound board. You could replace the motherboard if that is where the sound device is located. Or you can disable the sound in the BIOS and install an additional sound card and see if that helps.

10. During a blue screen (BSOD) - This can be due to a bad driver, bad memory, a stalled hard drive, BIOS or CPU problem. You should check your hard drive plugs and use the manufacturer's hard drive test utility. You should use the one made by your hard drive manufacturer, as the drives operate differently internally. Also, competitor's programs won't let you run advanced tests, or let you run it at all if you don't have one of their products. For some Western Digital drives, they will power down at random, and if one does it often, it may need replaced. You can often hear when they start powering up and down and then recalibrating (clicking sound).

In some cases, the wrong RAID or AHCI driver is installed. That will give a message about the storage device not being accessible.

If you get an error code, you should look it up and that will narrow the problem. Memory issues are a common cause of blue screens, so you should try different memory if you get that.

You can also check to see if you have the latest BIOS version for your motherboard. If you don't, see if the newer ones mention things such as timing issues, system stability, opcode fixes, microcode fixes, better CPU support, or offers more memory compatibility. A dirty secret is that most modern CPUs have flaws or bugs in them. What they do is have a system of microcode patches. The patches are loaded by the system BIOS and work around the CPU's bugs. So if the CPU manufacturer finds CPU bugs, they give microcode strings to the BIOS manufacturer to load right as the machine is turned on. Since the Pentium recall, both major manufacturers started using this microcode system for patching opcodes.

11. In general, but only while Windows is actually running - This could be due to malware, bad memory, a buggy CPU version, timing issues in the BIOS, Windows file corruption, etc.

What doesn't cause lockups - Lockups are not caused by "junk files" on the computer nor any "registry junk." Lockups are caused by malware, a buggy BIOS or CPU version, corrupt system files, a corrupt filesystem, a failing hard drive, bad memory, overclocking, faulty motherboard capacitors, bad CMOS settings (eg., overclocking the memory), thermal issues, etc. Deleting temp files and other "junk" to stop lockups is like placing a bandage on cancer or giving aspirin to treat HIV.