You can go to the Processes tab in Task Manager to see your running processes, but that probably won't help very much. If it were something like that, I would suspect that it could be one of your background utilities. And you're probably right in that it could be one of the energy saving ones that came with the mobo. You can uninstall the ones you don't need with their included uninstaller.
A freeze when coming out of locked mode could be either the screensaver or power saving software. Power saving is a problem because there are 3 layers: mobo/BIOS settings, Vista settings, and any installed utilities. Try disabling everything and see if that helps.
I thought some more and have another tack for you. "Moving around quickly" in a game would imply maximum 3D load and that is exactly where you would clip a power rail. Your Antec TruPower Quattro PSU has 4 12V rails with over-current protection, so any one rail can clip because each rail is pretty small, at 18A each (216W). The non-modular power cables seem to put the video card and mobo/CPU on the same rail, so it's entirely possible that the primary rail is clipping.
Try this:
1. Connect the fixed 24 pin and 8 pin connectors to the mobo.
2. Connect all of your drives, etc. to rail #2 with modular connectors.
3. Connect one of the PCIe connectors to the GTX 295 to rail #3 with a modular connector.
4. Connect the second PCIe connector to the GTX 295 to rail #4 with a modular connector.
This isolates the biggest power draws into separate rails and should avoid clipping, if that is indeed the problem.
If this still doesn't work, then keeping this same power connection arrangement that I've described, un-overclock your rig back to stock. On that basis, it is unlikely that you would exceed the limits of any one rail.
See if this reconfiguration works.