1. I believe "hang" could be caused by:
o Heat
o Bad Hardware
- Memory
- Old hard drive
- Motherboard?
o Software
- Application
- Operating System
- Driver
2. Overheating. Clean dust out of case, heatsinks, motherboard, case vents, fan blades, etc... Check to ensure all fans are working. Perhaps find software that displays temperature values of motherboard, disk drive temperatures.
3. Bad Hardware. Check the memory. Can run one module at a time. Don't forget memory slot could be bad. Use stand alone software to test. I recommend software:
www.memtest86.comShould be abe to find software to view the Self Monitoring Analysis & Reporting Technology (SMART) values on your hard drive. Find manufacturer diagnostic utilities for your hard drive and run them. Defrag the file systems. Wouldn't hurt to use "chkdsk" to verify integrity of the file system and perhaps hard disk surface.
4. Software. You could try running in "Safe Mode" to eliminate most of the software as a potential problem and see if problem reoccurs. If the problem does not reoccur, I'd suspect your third party device drivers
You could run "sfc" utility to check integrity of your system files, but fresh install probably took care of that.
Memtest86 is a self-contained system that boots from floppy or CD. If you run MemTest86 and system hangs, you know it's not a software problem because this software is independent of what you were running.
If it runs clean without hanging then it's probably not a heating problem, because the test exercises your system continuously until you hit "Escape" key to exit.
You could also run from a bootable Linux distro to eliminate your software as the problem.