The 'Joke.WinError' is a joke program. Being run it installs itself to system. It copies itself as WINERROR.EXE to \WINDOWS directory and sets system and hidden attributes to its file. Then it adds its execution to WIN.INI file after 'LOAD=' string.
When Windows boots up the joke program is loaded and stays resident. From time to time it generates Windows low-level error messages (big white windows) like 'Keyboard not connected' and so on.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Technical Details: Alexey Podrezov, F-Secure