Quote Originally Posted by Greyskull View Post
If it was due to overheating, you'd want to add more things to it than just cream, say like if upgrading the cooling system by say replacing the cpu fan to a water cooling..or changing the case, tidying cables up, all adds up

Or the absolute cheaper option of reverting back to defaults..
airflow is a major concern. ribbon cables can block airflow, hard drives too close to each other, etc.

For that matter, it could even be a bad cable connection to the boot drive. The system will hang while trying to access it.

More info is needed. Does the computer ever lock up just sitting there? What is the user doing when it locks up? This can tell us which parts of the system, if any, are under stress at that time.