Perflib and Perfdata stands for Performance Library and Performance Data of Your computer. If By any chance, you thought it is a virus, then let us assure you that it isn't.
It is a log file that the System generates automatically whenever you switch on your computer and generally gets deleted once you switch it off. Though sometimes, when you shutdowns a computer by pressing the power button directly, these files get remained.
We would suggest you not to delete the files.
But if you still want to delete it, Here is a procedure that shall help you:
- Click on start>run and the type perfmon.msc and hit enter.
- A new window will come up showing a real-time graph of your computer's performance.
- on the left hand side, click on Counter Logs under System Monitor
- Now on the right hand side, you will see System Overview. Double Click on it.
- Now keep clicking the Remove button until the counters list is empty.
- Click on OK