Static in right channel at higher volumes

New to the forum, thanks in advance for your attention!

I'm experiencing slight static in the right channel on my PC (Windows 7 Ultimate x64). This happens with all equipment I use, including multiple pairs of headphones and my Bose Companion II speakers. It happens whether I'm using my motherboard's onboard audio or my Creative Soundblaster X-Fi sound card. I can only think it's a software issue, most likely driver conflict. All of my drivers are up to date (6.0.1.1375 for the Creative card--RealTek is disabled in the BIOS right now but I can reactivate it and check if necessary). I suppose a motherboard problem is also a possibility. BIOS and all relevant drivers are up to date.

It's most noticeable in music files regardless of format, but occasionally in movies and videos as well, depending on the frequency range (seems more noticeable during emphasis on lows and mids). It's more noticeable playing through Winamp than WMP, but I think that's just because of the equalizer/sound differences.

I found a YouTube video in which a user had severe audio distortion when his Logitech G510 keyboard was plugged into certain USB ports as opposed to others. I have the same keyboard, but my problem isn't nearly as extreme as his was, and I don't have another keyboard to test it at any rate. Changing USB ports was ineffective. I've tried rolling back drivers and such already.

Any thoughts would be appreciated! If you need more information, let me know and I'll do my best to provide it.

Thank you for the suggestion, I'll try that out later tonight when I get the chance.