Provide us with the following answer and checks to understand the problem better and get some clues:
1. How often does it freeze?
2. How long after startup?
3. Under what circumstances, or what applications running?
4. Does it unfreeze by itself, how long do freezes start? or do you have to restart?
5. What are the system specifications?
6. Year (+/-) of purchase?
7. Type of computer
8. Check Start\Run\type: "msconfig" (no quotes) Enter and, check on the Startup tab, how many startup programs you have running and their names.
9. Can you see or check the processor fan is running?
10. Also check the Taskmanager (right click on taskbar\Taskmanager) and check the Process tab,.. count the processes running, what is the % for System Idle process, and what process is the highest in Memory Use. Upload a screenshot of the Taskmanager if possible... and even of the Startup Tab in msconfig. Cut the images to the taskmanager and Startup windows only for better definition. http://www.imageshack.us/