My problem is: the computer wants to start, the fans kick in, then a second later the system shuts down completely.

I've searched through previous threads and can't find one that really applies to my problem. Any help would be greatly appreciated!

Our desktop is an HP 533w (a gift from my brother in law). It worked okay for a while, although the PSU seemed to be faulty. Basically, the computer would randomly shut down, and then wouldn't start up. A couple of times my husband cleaned it with compressed air, and it worked okay for a while, then started with problems again. Eventually it stopped starting up altogether.

I thought it might be the PSU so I replaced it with a larger one (it was a 200W, went for a 400W). No dice.

I think it may be the motherboard. HOWEVER... when I was installing the new PSU I had to remove the cooling fan off the CPU and found a greasy gray substance on it. Could this mean that either the CPU or motherboard are done?

Thank you for your help!

Hello and welcome to Techspot.

The gray greasy substance is the thermal paste/pad. This is required to help with the heat transfer from the cpu to the heatsink.

If you haven`t applied new themal paste, then there is a good chance that your computer is shutting down to prevent damage to your cpu, because it`s getting hot.

Unplug your computer from the mains, and open the case.

Make sure you are grounded by touching the metal chassis of your case.

Take off the heatsink, and clean off all the old thermal paste/pad from the heatsink, and the cpu, using a little isopropyl alcohol etc.

Apply some new thermal paste to the die of the cpu. Only use a very small amount of thermal paste. See HERE for instructions on how to apply thermal paste.

Reattach the heatsink carefully, making sure you put it on the right way round. Plug the cpu cooling fan into it`s socket on the mobo.

When done, start your computer. Hopefully you will be lucky, and everything should work ok.

Regards Howard :wave: :wave:

Thank you! I'm definitely going to try that. Is the Arctic Silver available at any hardware store or do I need to go to a computer specialty store?

Anyway, I went back to the computer to check on a few things and I think I got things up and running.

I took out the CMOS battery for a few minutes and put it back in. I then checked the heatsink fan and it wasn't plugged in properly, so I reset it.

I then took out the memory and reset it.

Now the computer is booting up, no problems!

It must have been the PSU after all.

I`m glad your computer is now running ok.

However, because you have broken the seal between the heatsink, and cpu. I recommend that you do get some new thermal paste. It doesn`t have to be Arctic silver, although it is supposed to be the best.

You can get themal paste from any pc shop.

Untill you get the new thermal paste. Keep an eye on your cpu temperatures. Download the Speedfan programme from HERE It`ll tell you what temperature your cpu is running at.

Regards, and good luck Howard