I would suggest a general freezing question, and only allow more specific cases that have rich detail and went through the whole procedure.
Some resources for the FAQ question/answer:
Dumping the freeze:
Hard Freeze: CrashOnCtrlScroll, to initiate a manual crash dump.
Soft Freeze: ProcDump (former ADPlus), to initiate a dump of a hanging process.
Troubleshooting the dumps:
Make sure that automatic restarts are disabled and the memory dump settings are right.
WhoCrashed, to check the dump to see if something obvious is hanging the system.
Debugging Tools for Windows, for in-depth analysis of the dump.
Troubleshooting the computer:
Check the event logs, just in case they caught something...
Make sure your BIOS is up to date, the BIOS settings are right and no overclocking is applied.
Disconnect any hardware that you don't need, to rule it out.
Check the temperatures, clean the fans. Check the connections, cables and transistors.
Check for incorrect motherboard voltages in the BIOS, correct them there.
Try to update all the drivers, remove unnecessary boot entries and software.
Other reasons:
- Insufficient/problematic PSU, replace it by a more powerful one.
- Corruption or faulty system drivers beyond a level that you could fix, a reinstall is required.
- Faulty hardware, try to replace individual components with spare parts to see if it has an effect.
- Still have issues? You're asking too much of your system, give it a rest and upgrade... :-)