I recently upgraded to Windows 7 Ultimate (without reinstalling, an actual upgrade) and now I'm experiencing some really annoying mouse lag in Chrome. It seems to happen most often when there is a Flash element on the page, though that's not always the case.

I have a Windows Experience base of 7.5 (I just re-ran it), 7.7 in desktop and gaming graphics, and Skyrim still runs fine. I ran an Intel chipset update and re-installed my Catalyst drivers (I uninstalled them first), and I don't have any available Windows Update. I've also re-installed both Chrome and Flash, and I've disabled all of my Chrome extensions. Nothing has helped.

What might be causing this very annoying issue, and what might I do to fix it, short of reformatting?

Thank you.