Playback often spool forward

[Stramm]

I have problems with the playback of movies, avi and mpg´s. Often in a minute they spool some seconds forward at the playback.

I installed windows xp with all updates repeatedly, the latest divx and many players but this problem stay.

my system: nforce2 board, xp2600+, 512Mb ddr Infinieon, GF4200Ti, etc.

I hope somebody can help me.