Run Memtest86 see if that comes up with any problems. Clean disk, defrag, and run CCleaner to clean the registry. Run a FULL scan with your antivirus. Run a FULL scan with MalwareBytes. Are you overclocked at all? Have you monitored your CPU and GPU temps at all see where they are at? Is this a new build or has it been working previously, how long? How big and old is the PSU? When are the freezes happening from boot on, from log on on, while on the internet, while playing games? Try updating your audio drivers, and video drivers.
Windows 7 Ultimate 64 bit Randomly Freezes
No BSOD just random freezes with screen on and no keys or cursor repsond, all I can do is use a hard reset to restart. Then I get the standard windows was not shut down properly messege at start-up. I have been having this issue/s and have tried all the same standard help people have had to offer, in all the dfferent post I've read online.
To actually fix this issue I ended up having to go to the device manager and check for driver updates on all my devices, one at a time. I think the ones that had updates that fixed this issue were the ACPIx64-based PC under the computer drop down and the IDE ATA/ATAPI controllers especially the ICH ATA and SATA AHCI ontrollers (I think these made the difference). I checked them all, but these were the only ones that had updates. Once those were updated and the computer was restarted, it has stayed on. It's been on for a day now and no problems so far.