PROBLEM:pc shutdowns even before the first screen

[saurabhsun]

i have this problem with my pc that it automatically closes (directly stops) when i switch it on. it happens at different times.....ranging from when even the first booting screen appears to working for 15min. then the power button stops starting the comp. then i have to pull out power cable and put it back to restart again. after it closes 3-7 times, it works fine. can it be due to the functioning of the pc fan which sounds very loudly first and noise slows down after sometime (say 3min.)?????

my ram is 512 and 10 gb of free space on internal 40gb harddisk and 10 on removable external disk of 80gb. windows 2000 and xp on c and d drives. p4. dvd writer and seperate dvd rom......

i have received the same problem when i removed the ups and did direct connection and i have also tried using another power cable.

plzzzzzzzzzzzzzzz help

[Cool G5]

I think the problem is with ur power supply.Get it checked from a technician.The fan cannot be the cause.Some pc have variable fan speed which increases when the pc is under load(during booting).