An overheating or border line overheating machine can result in lock ups, slow downs, and unexpected reboots. To find out if your CPU is too hot you'll need the "hardware monitor" that comes with your motherboard. There are also plenty of third party programs which you can run.

The next question is "how hot is too hot?". Intel CPUs display one of two numbers... an absolute temperature ~or~ a thermal margin. The first is self explanatory but the second can seem confusing. The Margin indicates how many degrees remain before the CPU is critically hot. So the bigger the margin the safer you are.
Remember that modern computers conserve energy when idling, so run you most intensive application for 30-60 minutes and keep and eye on your temperatures. Conventional wisdom indicates you want your mobo and CPU less than 60°C (140F). Any higher and damage to one or the other may result. Intel has specific details on each CPU including its thermal maximum on this page, click here. Most modern CPUs give you a thermal margin which removes the guess work.
Tip... if your hard drives are too hot to keep your hand on for any period of time then you have excessive heat build up. Ensure hard drives have one drive bay gap between it and anything above it. Or use a case with hard drive cooling fans (see below).
If your board and/or CPU are running too hot you should consider a well ventilated case. I am now using the Antec 900 (click here) which has four over sized fans plus the fan in your PSU making five total. The 120mm BIG BOY (their words not mine) is placed directly above the CPU keeping it super cool.Hopefully these tips will help those users experiencing weird hang ups and crashes.
Tip... if your temperature is good but file access is slow and you get lots of blue screens then there may be a chance your hard drive is about to fail. Make sure to run a check disc or similar application. And always make frequent backups!

