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I have decided to clean my computer. I opened it, removed the fan from the CPU and cleaned it. It was jammed with a lot of dust. After I put it back, and it rotates much smoother and better, I started to get CPU over heat error. I never got it before. It's a bit ironic that after cleaning the fan my computer hangs and send a CPU over heat error. After restart it says "CPU overheat, press F1 to continue".

I think of two options:
1. I miss located the fan over the CPU and so it really overheat.
2. I somehow ruined the heat detector and it thinks it's over heating.

I even tried to disable CPU temperature monitoring in the BIOS, and yet, the computer auto-restart and says CPU overheat.

What can I do?
How can I know that I have placed the fan correctly?
How to know if the temperature detector is OK?

The computer I have is ASUS pundit 350:

Thanks. Aviv.

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If you took off the fan and therefore expose the CPU, did you then apply more thermal paste or notice if there was enough? – Dave Apr 12 '13 at 9:19
Does the BIOS give you any indication of the speed the fan is running at? Just because it looks OK, it may be running slower – Dave Apr 12 '13 at 9:26
Did you remove the fan from the heatsink or the heatsink from the CPU? If the latter, you have to understand how to properly mate a CPU with a heatsink. If not done exactly right, the heatsink will work very poorly. – David Schwartz Apr 12 '13 at 11:09
More information is required. What processor are you using exactly? I don't believe it to be normal for the stock cooling unit on either AMD/Intel processors to be removable. Which means you removed the heatsink from the processor and likely didn't replace the thermal paste. – Ramhound Apr 12 '13 at 11:32
@Dave, Yes I removed the fan with the heatsink ... and no, i did not add thermal paste (I didn't even know it exists ...). Stupid me. Anyhow, I will buy some paste asap and add it. Hope it will solve the problem. Thank you all for the help. I really appreciate it. – Aviv Apr 13 '13 at 12:26
up vote 3 down vote accepted

Most likely is that you CPU fan is not properly anchored. This causes that the metal could not lead away all the head.
Another thing could be, that there is too little heat paste (the white sticky stuff).

Best thing for this problem is to clean your CPU and fan and apply new paste on one (!) side. Spread it a little so nearly all of your CPU is covered. Don't take too much 1-3 pinheads of paste should do it.

share|improve this answer
Great. I will check it. I never knew there is a thermal paste that you need to put, I will buy one. And the fan connectors are very difficult to attach. I am not sure its properly located. How do i make sure? – Aviv Apr 12 '13 at 9:57
it looks something like this it has 3 or 4 connectors. It makes a "clip" sound if its attached correctly. When you turn on your computer please verify if the fan is actually rotating – syss Apr 12 '13 at 10:19
@Aviv: If you're going to apply thermal paste be sure to clean the existing dried paste. Too much is actually detrimental, you only need a very fine layer. There are lots of YouTube videos demonstrating proper application methods. – Karan Apr 12 '13 at 15:03
@Dave Rook and syss, I used the thermal paste - worked like magic :-) – Aviv Jun 26 '14 at 12:11

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