Weird Problem regarding Boot-Up

I have a P4 2.4 ghz pc with 1 gb ram and geforce fx 5200 graphics card. I recently got my motherboard and ram changed as they were not working properly.After that, my pc is working smoothly without any problems, but this one! After i run my pc for about 2-3 hrs., if i then shutdown it, and try to turn it on again after around 2-4 hrs. using the power on button on cabinet, it does not turns on. No response on the push of button happens. It is only after around 5-6 hrs. of last runtime that the pc can be turned on again.Rest the pc is working ultra fine! Can any0ne help me?

Thanks.

 

it could be because ur cpu is getting too hot, and hence it refuses to switch on. only once it has cooled is it turning on again. i'd suggest u check you cpu fan before you damage your processor.

peace..
aditya

 

switching off from ups, what does that mean, please explain!

 

the temperature is too hot here in bhopal, and i checked, fan is working! i guess i'll have to keep the ac on in the room!