When i press power on button of cpu for start the system, the systems has start but suddenlly shut down of off whole systems. give me slolution for fix this problem

I had a problem with my IBM but i just changed the power supply an it was ok, then I had the same problems with a different machine but its a similar IBM version Itried to change the power supply but it didnot work out.

Hi Vedant,

first of all I would check the cooling fans, particularly the one for the cpu, you will see if it is spinning if you remove the side case. (DONT TOUCH ANYTHING INSIDE WHILE THE PC IS SWITCHED ON) If the fan is spinning ok, then check for dust build up around the cpu cooler. If it needs cleaning, switch the machine off first and unplug from the power supply. Touch a bare metal part of the case before attempting anything to discharge any static electricity you have in your body. Clean any dust build up away and try booting the machine again. If still no joy, Check your RAM modules, try removing them one at a time to see if one is faulty. If you have more than 1 stick of ram, make sure when you remove one, to put the remaining module into the slot closest to the cpu.

I hope at least some of what I said turns out to be helpful to you

Overheating. The shutting down is a fail-safe. You need to first open your cabinet and check your fans and make sure that your computer aren't filled with dust. If it is blow it out with air duster and it should solve the problem.
If your fans have failed, you'll need to replace them. If they haven't, your next step is to increase their speed. The utility below will monitor you temperature and increase your fan's speeds to keep the system cool. If you are unable to cool your computer down to the point where it stays on, your power supply had gone bad and needs to be replaced.
http://www.almico.com/speedfan.php