VLC Having Trouble With Video Media

[Prodiege]

VLC has always worked fine for me, but after a fresh OS install, VLC doesn't play most videos the same. MPEG files play perfectly until about 60% through and then the audio and video is glitchy, very glitchy. I was also playing a full length movie AVI file recently and during the second half of the movie, the video had a lag time behind the audio so the words didn't quite match their mouths. These same videos work well on any other players (not ones I prefer though) so I'd prefer to fix whatever is the issue. I run windows XP Pro SP3 with a 2.01 Ghz Processor and 2 GB of RAM.

Thanks ahead of time for any help