Okay, I finally got around to buying some virus protection software (Norton SystemWorks) and utilities for my computer. I ran the virus check and found about 500 files infected with the win32.pinfi virus. I was able to clean/fix 499 of them. The last file infected with the virus is winlogon.exe. Access to the file is denied and Norton is unable to fix the file.
Click Start, and then click Run. (The Run dialog box appears.)
Type regedit
Then click OK. (The Registry Editor opens.)
Navigate to the key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
In the right pane, delete the value:
“Windows Logon Application”="%Windir%\winlogon.exe"
Exit the Registry Editor.