Out of nowhere, audio began stuttering on certain things

[Exai]

Two days ago, for no discernible reason, my audio started stuttering and getting choppy under the following circumstances:

When watching a video on a non-youtube site in full screen (twitch.tv and own3d for example).

When the windows start up sounds play.

Audio pops and crackles when clicking any browser tab (IE, firefox, chrome) on the task bar, and when switching tabs while browsing.

Audio and video files on my hard drive play fine windowed and full screen with no audio problems.

The problem started completely out of nowhere with no new driver updates for almost a week before the problem started occuring.

I have rolled back all possible drivers anyways, and updated them completely fresh which did nothing to solve the problem.

I've been working on this for a couple days and have yet to come up with a concrete answer as to why this suddenly began.

My specs:

Windows Vista 64-bit

Intel Core2 Quad CPU Q9300 @ 2.50 GHz 2.50 GHz

Nvidia GeForce GTX 650 Ti

Creative Soundblaster X-Fi Titanium

Any help or theories are welcomed. Let me know if you need more information.

 

[Exai]

Problem solved. I don't know whether it was the disk defrag or error-check that did it, but one of them succeeded!