Stuttering Video/Audio

Hey guys,

Hopefully I'm posting this in the right forum. I'm having excessive stuttering on audio and video playback (perhaps at other times, although media seems the most noticeable). The issue occurs whenever I watch anything - movie files, youtube, itunes audio, etc. Of note: this is NOT a new issue. It's my wife's computer, and has been going on as long as I can remember.

I've tried a quick google search and used tools such as DPC Latency Checker, LatencyMon, and windows performance analyzer. All I've been able to confirm so far is that:

a) I have some serious DPC spikes. At one point I recorded a latency of 175396 μs, significantly higher than the normal 139 μs.
b) My original suspicions of it being due to a network driver have been cleared. I've disabled both my wireless driver and my ethernet driver, and the stuttering has continued.

I'm looking for help from somebody who has a little more experience than I in these matters.

Here are some specs. LatencyMon seems to have excellent logs, in case they are requested.

SYSTEM INFORMATION
_________________________________________________________________
Computer name: STEPHANIE-PC
OS version: Windows 7 Service Pack 1, 6.1, build: 7601 (x64)
Hardware: Satellite L650, TOSHIBA, Portable PC CPU: GenuineIntel Intel(R) Core(TM) i3 CPU M 350 @ 2.27GHz
Logical processors: 4
Processor groups: 1
RAM: 3894 MB total


All (or any!) help is much appreciated, thanks!