Open Windows Explorer. Go Tools>Folder Options>View tab, put a checkmark next to Show hidden files, and folders.
Upload following files to http://www.virustotal.com/ for security check:
- C:\WINDOWS\system32\winlogon.exe
- C:\WINDOWS\system32\svchost.exe
IMPORTANT! If the file is listed as already analyzed, click on Reanalyse file now button.
Post scan results.