Hi recently i have been having prolems with over heating i think.. it use to stay around 70c and lastnight it went up to 90c and now everytime i have to computer on for more than 30 sec it goes above 100c according to the motherboard CPU heat sensor. I was wondering if you think it's the CPU or the mobo sensor?.. i have a 2.66Ghz celeron D processor and MSI mobo .. i can get the modle if you need it.

Remove the power to your case, open up your case, and take a look at the cpu fan and heatsink - you may find that both are filthy. If that's the case, clean them off, preferably with something such as a small artists brush that has natural bristes. If you use a vacuum cleaner to clean with, the case must be plugged in with the power off, or grounded electrically some other way - vacuums produce a tremendous amount of static electricity that can easily damage components on your computer otherwise. You may need to remove the cpu fan to properly clean the heat sink. Once both are clean, restore the power to the case and boot the computer. Look at the cpu fan and make sure it is spinning properly - if it spins very slowly or makes any kind of squealling noise, or doesn't spin at all, you need to replace the cpu fan immediately. Running your computer for more than a few minutes with a dead or too slow cpu fan will allow your cpu to get hot enough for it to be damaged, or burn it out. If you need to remove/replace the cpu fan, remove the power to your case while doing so.

i went and bought a new Heat sink and fan today still hasn't fixed the problem..

It's highly unlikely that any of your temps actually got up to 100°c. The problem could very well be with your sensor software. I had a similar problem with my PC ... kept getting bogus temp readings that would actually trigger an alarm on my m/b. Finally had to disable the sensor software, and never had a problem with it after that. BTW, you said you replaced the heatsink/fan on your CPU. Did you clean the old thermal paste off the CPU and apply a fresh thin layer between the CPU and new heatsink? 1 Corinthians 15:3-4

Yes, it is possible mboard monitoring software you use in Windows could be improper for the sensors on your mboard, but it is very rare for the sensor on the mboard to yield you a cpu temp reading that is off by more than a few degrees in the bios Setup current readings. You must install the heatsink properly on the cpu, including making sure it either has good thermal contact to the cpu with thermal grease or paste, or good thermal contact to a very thin thermal pad already on on the bottom of the heatsink if it has one (it may have a protective film on it - if you have one of those, did you remove that if present?) It is possible to install some heatsinks backwards so that they are not sitting flat on the cpu.