Answer:
Identifying a virus is the easy part. You may have a virus if you are noticing slow performance, and very odd behaviors of your computer, such as blue screens, random crashes, and others. The hard part is removing it. In order to remove it, you will need to have an up to date AntiVirus software. By the way, do not use Norton, McAfee, or Kaspersky. All those big Antivirus names are just huge sellouts that do not really protect against anything. That's why free AV software is the best, like AVG, MSE, Windows Defender, or my personal favorite, Malwarebytes. Once you have your AV software set up, start up a scan. Once that is done, it will most likely have found your problem, and you may remove the virus.