Sound crackling ONLY in video games

[sindraim]

So I've had this problem for about a week, whenever I launch a newer video game, the sound is crackling. And I mean the ambient music and dialogue are skipping a few miliseconds. Nothing like this happens outside of games, I can play music and youtube vids in HD just fine. My GPU drivers are not up to date but I'm downloading the drivers right now. My sound card had no updates for a long time. Also, Mass Effect 3 worked fine a few months ago. How can I fix this?
Specs -
ASUS M2A-MX mobo
Nvidia GeForce EN9500GT 1gb
Windows XP SP3
1 GB ram
AMD Sempron LE-1100
I don't exactly know my sound card, sadly, but it's a very low end Trust 5.1.

 

[djosbun]

Can something else be interfering with the audio? Keep the task manager open and see what your hardware is peaking at during this audio issue.