Tricky XP mouse problem…

This one is a bit weird…
I have a USB mouse that was working fine on XP but then i reformatted and found that it was really jerky around the screen (like it was loading), i then found that when i played music or video the mouse returned to normalright up until when i stopped playing the music or video… I have all the latest drivers and have found that when i use a ps/2 adapter it appears to work fine….
Any help would be appreciated.