When installing different dvd players, I finally ended up
with not being able to play vcd or avi films.

I get the information from WMP 10 that codecs could not be loaded.

I get also error messages:
1. The source filter for this file could not be loaded.
2. Director player error

I tried to reinstall WMP 10, reinstall all different codecs that I had
(including WMP 7+ codec pack), tried to install other new codecs,
and reinstall audio, video, and monitor drivers. But nothing helps.
I get exactly the same error all the time. It is as if the codecs can
be installed, but that they don't get contact with the multimedia
devices (I tried WMP 10, several DVD players, and several VCD players).

My son has many VCD films, and he's sorry now. Please help!

Yes. One more thing. I have of course tried uninstalling the DVD players that caused this error
in the first place. /A

Have you tried a system restore back to when all was working?

Dear brain_damage. Your help was invaluable. A system restore to
a previous state did the trick. Now, the computer is working impeccable.

This deserves a donation!

/A