WMP out of sync. AGAIN!!!

WMP 11 again playing audio/video out of sync when playing avi/asf/asx files. It has just started doing this after previously (at least 2 years) playing these same files perfectly.

I tried rolling back to WMP 10 and reinstalling 11 but to no avail. When I did this it wouldn't play avi files AT ALL until I installed a new codec??? I'm really tearing my hair out now. Why has it started doing this? Running XP SP2 with 1gb RAM and 13gb free HD.

PLEASE HELP!!!

 

Does it play fine in WMP 10?

When was the last time you defragged?

What codec are you installing?

 

I haven't tried WMP 10 as only got 11 installed. The codec I've installed is the Xvid one that it prompted me to install, although WMP 11 always used to play avi files without the need for me to install any codecs. I've just done a defrag and that hasn't made a difference. I just don't understand why things have suddenly changed.