I recently discovered that CPU temperatures of 55-65 are bad on Pentium 4's. Could such high temperatures have been causing increasingly-frequent CTD's?The CPU fan runs, my case is cooling itself, but I'm thinking the thermal wax between the heat sink and CPU might have degraded. If this is the case, and I replace the heatsink/fan and add new paste, will my processor be ok, or is it permanently damaged?

I had the same problem with my p4 CPU, and yes it can cause crashes, hangs and other problems. Those temps aren't too bad, mine where higher around 69-70 and I was having problems. It varies. I took out the processor and found that the heat sink was caked with dust. A good clean out and some new Artic thermal paste dropped the temps 10-15C or so. I believe the Intel recommended spec is around 45c, but mine was operating well at 50-60 prior to the issue. Chances are, if your computer is fairly stable, there is no damage to your CPU.