Computer Restarting, CPU very hot

[joe_cronin16]

My cpu is getting very hot very quickly, and it doesn't have time to start windows before it restarts itself. At first, I thought it was the power supply, but then I went into setup and checked the temperature, and the cpu temp was 65 degrees C. and rising.
I have a:
Pentium4 3.0 GHz processor
1 GB dual channel ddr 2 ram
dvd burner
300 GB HD
GeForce 6600 GT
It hasn't been on the internet for a long time, nor have I changed anything as far as hardware or software. It is kind of dusty, but if a cpu isn't getting good airflow due to dust, would it really heat up that quickly? I was playing oblivion a lot, then it just starting restarting. As time went by and I didn't do anything, it was taking less and less time to restart itself. Now it's at the point where you can't get to windows, and it will only let you look in setup for maybe 3 or 4 minutes tops. If anyone knows why it's doing this please help me out. Any ideas or pointers on what is wrong will be greatly appreciated. Thanks in advance.

[honvetops]

questions*
What type of [highlight]motherboard[/highlight] do you have ?
Are you using the "stock" intel  heatsink/fan  < ?
did / are you cleaning out the dust and crud inside the case.

Have you overclocked this cpu  before ?

[joe_cronin16]

I've got a Gigabyte 315g chipset, I'm cleaning out the dust to see if that helps, and I'm using the regular heatsinks that came with it, but It's a custom build, and it was working fine for a long time, at least a year. Also for the last part, no, I've never risked overclocking anything.

[ale52]

Could be the CPU fan isn't spinning up to speed.  Open the case & boot the system.  Watch the fan.  Does it make any kind of noise other than the fan spinning (grinding / whining)?

Alan <><  

[joe_cronin16]

no, it's not making any strange sounds, but when I go into setup, the fan starts off at around 1500 rpm, then quickly climbs to around 2400 rpm. I'm guessing that as the cpu gets hotter, the fan is having to work harder. It gets to about 2500 rpm before it shuts off.

[joe_cronin16]

Ok, I cleaned the dust out from the cpu fan and it must have been so thick that it wasn't getting ANY airflow, because now it's working fine and it's not restarting anymore. I feel like an idiot because it was so simple a problem, but thanks for your help everyone anyways.

[CBMatt]

Ok, I cleaned the dust out from the cpu fan and it must have been so thick that it wasn't getting ANY airflow, because now it's working fine and it's not restarting anymore. I feel like an idiot because it was so simple a problem, but thanks for your help everyone anyways.

Well, the sheer simplicity of certain problems is sometimes what makes them so difficult, so don't feel too bad.