>>5
There seems to be some confusion. If you run Windows as the operating system on your computer you have folder called "System32" which is part of the OS.
However, there is a virus called "system32.exe." This file is a Trojan; a spyware file; designed to send information about your activities, which has been picked up from opening malicious emails or visiting dubious sites.
It is old by malware standards and may be removed using free programmes such as Adaware, Spybot Search and Destroy, Superantispyware, as well as commercially available programs. If it is hard to get rid of, Combofix another freeware program, will deal with it at some risk to your system.
The reason why a PC is running slowly is probably because if you have system32.exe, it means you haven't carried out much housekeeping and you have a lot of malware as well as temporary files and so on. Programs such as CCleaner, Cleanup!, Cleandisk, Windows Washer, and Easycleaner (all free) should speed up your OS by removing the unnecessary clutter it has accumulated.
Linux is an alternative operating system, not a virus removal program, though running it instead of Windows will certainly prevent your getting system32.exe. It is a freeware operating system using open source code, built by enthusiasts and available to anyone. It is far more stable than Windows, which is why many large organisations such as IBM are moving to it and Google run their servers using it.