I have a problem about the computer that always shutdown, and i dont know what is the problem if it is a fan or the PSU... After using for an hour the computer is shutting down.....

can you tell me what can i do?

this is the specs
Pentium 4 intel inside 2.40 GHz
512 MB Ram
Nvidia GEFORCE4 MX 440 with AGP8X
40 GB HD

:knock: :knock:

it could be many things, temperatures, hardware, power, programs etc.

how is it shutting down? just power off or through the shutdown process? can you start your PC immediately afterwards or do you have to wait for a bit?

Read the guide linked below, even if its aimed at game problems it should be useful info for you to start troubleshooting at.

Where you live is very hot with a lot of air pollution - have you checked that all intakes, heatsinks and fans are clean and operating?

it didnt start immediately and i waited for 5 minutes but i need to pull the black cord at the back where it attached at the PSU and after 5 minutes i put back the black cord at the power supply. Its Always like that...

sounds like temperature to me... if you can leave that power cord in and still have to wait ~5 minutes..

unplug the PC and open the side access panel/case. Give it a good dusting with some compressed air or a vacuum cleaner. Note the fans and the heatsinks.

Follow the link in my guide to get a program called Everest Home, and read up in part 2 about temperatures.

I open the access panel and clean.... but still the same of my problem.

follow the link to my guide. it may be for games but its at least something to start you off finding the fault. post report from Everest and your PSU info.