powerDVD refuses to play mpg files

[Proficat]

I have a win2000 with the nimo codec pack 5.0. When i try to play a mpg file, powerDVD simply does nothing. While others (like divx,...) work perfectly correct. A while ago, after 5 times closing and opening powerDVD, I managed to play a mpg file. But even that doesn't work enymore. Reinstall does not fix the problem. Any idees?

thanks in advanced

Greetings