lost sound on certian movie files

[dameon1313 0]

downloaded some codecs for video and sound play back and lost sound runing xp tried removing all the codecs that i could find and re installing certain one that i know worked before i put the other codecs on the computer did not do any thing tried rolling back fixed problem then reinstalled windows midea player 10 problems started agian tried everything but unistalling windows xp and the partion don't want to did it 30 days ago pain in the ass if you can help me so i don't have to uninstall and then install xp that will be great starting to piss me off been like this for 10 days all mp3 work but not all mpeg work tried installing xp codec pack think it might be a bad codec pack not sure im good with computers "going to collage for it" but this ones got me stumped. been able to fix every other problem so far

[Relic 0]

Couple questions, first one being: What are your system specs?

 

Are you running with onboard sound, or using a sound card?

 

If you're running with onboard sound, have you updated ALL your mobo drivers?