deadshots :
Thanks for the reply. I ran CCleaner it fixed various little problems, and I also ran memtest and it came back clean. It's still freezing though
Well... if your memory came back good and you ran CCleaner's Clean and Registry portions both until they returned no more items to fix, I would next rule out a driver conflict. First check to see that there are no exclamation marks in Device Manager.
Then (unless you've already done this) uninstall the gfx driver, run Display Driver Uninstaller (DDU) following the instructions here: https://forums.geforce.com/default/topic/550192/geforce-drivers/display-driver-uninstaller-ddu-v12-9-3-4-released-06-09-14-/
Re-boot, run CCleaner again, and then install the latest driver for your card and OS.
http://www.geforce.com/drivers
Do you have a lot of stuff starting up with Windows? Check your tray for stuff you can disable. Also check System Configuration/Startup for boxes you know you can uncheck. Try to eliminate as many items that can be poorly written code that steps on other programs.
If still no joy, temporarily replace the GTX 660 gfx card with another one by doing the driver uninstall routine above. See if the issue is gone.