Since your original post implied that SP3 started these problems, why not try
uninstalling it and revert back to SP2?

If all is well afterwards then reinstall SP3 but be sure to deactivate your
anti-virus app before doing so.

Other than that, I'm out of ideas.

Good luck!

"wernertk" <wernertk@discussions.microsoft.com> wrote in message
news:6ABFE5D6-ECF2-4090-8854-48A23C5A9B81@microsoft.com...
> System Restore did not fix it.
>
> Something strange though. I wanted to see if adding virtual drives would
> help, and when I added one (virtual cd drive) the "explore" option for My
> Computer disappeared... When I right click My Computer, I can only open it.
> There's no option to explore it.
>
> Pressing WinKey+E gives me a "The Parameter is incorrect" error box, and
> explorer does not open... mmm. Hope this can be of help. Adding the regkey
> entries in the link you provided earlier, gives back to option to "explore"
> My Computer.