Computer problem

[MikeyMouse]

So basically my PC has all of a sudden started having 'performance' issues. For example playing a song in Itunes, it will slow down, speed up, lag, and sometimes all together stop the song, as if it's struggling to play the file. This is the same with videos on youtube, as well as on windows movie player.

The main reason I want this issue sorted is because it's happening on sony vegas as well. I click play to view what I just edited, and it speeds up to about 1.2x the normal speed, then after a minute, stops completely and moves at one frame every minute or so. I haven't changed anything on my PC, everything else runs perfectly fine (games, searching online, things like that) but as soon as I ask it to play a song or a video, it just fucks it up.

 Any solutions?

[Cookie]

Update graphics drivers
Create a system restore point if you want