odd sound problem

[timmyg]

hey guys,
so recently the sound has started acting very weird from my pc
every so often it starts making this weird static noise that sounds kinda like a spaceship flying around (i've heard this sound before by leaving speakers plugged into my tvs headphone jack after i shut the tv off)
now its gotten worse, for some reason it seems like when i try to play videos in windows media player or any other media player the sound doesn't work at all or it plays sluggishly, slowed down so it sounds weird
and now its gotten even worse, sometimes when i play a video it runs slow or stops until i pause it and play it again

i've never encountered any sorta problem like this
at first i thought maybe my sound cards just starting to break but it doesn't seem like it anymore since videos are running poorly too
this could maybe be a virus but i've scanned and gotten nothing too serious, don't really have many ad-ware/spy-ware problems

i recently installed a new video card and dvd-burner but my sound and video worked fine with them for like 2 months before this new issue started
i've tried reinstalling my sound card drivers

my parts:
windows xp pro with sp2
soyo dragon 2 platinum mother board
M-Audio Revolution 7.1 sound card
ATI x800XT video card

[timmyg]