I don't think your CPU Is fried
If it was I don't think it would boot your computer
might be your hard drive but I would give it a 10% prob it would be that
Corrupted system files might be the case as well
If you can Try to set up a temporary partition on your hard drive if you got a 500 GB hard drive make a 20 GB partition and install windows on it and try it out
If it doesn't freeze on the fresh install of windows you got yourself your answear.
and from there when you are in the partition manager Resize your current partition and make it smaller about 20 gb less so you can leave space for a new partition
Do a youtube search on it to make it easier
51C is not that bad a little high but compared to other people I have seen their processors go up to 80-90C and that makes their computers freeze
Sata HD are faster than belt or are better reffed to as ATA or many call it IDE
Sata is also newer than ATA
from your hard drive GB amount I think you may have a ATA
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.