For the past 2-3 days my computer has been automatically turning off. I can think of three reasons:
I have very cheap grade power supply and it may be that it is not able to supply enough power, so if power requirements increase the computer turns off.
My hard disk is faulty because the following has happened to me twice: when I restart my computer it says "disk not found". Then I turn it off, wait 5 minutes, start again and it's working again.
Maybe my CPU is overheating and cuts off the hard disk.
I don't know what is the problem. Is there any way to find it out?
A few additional notes:
My computer always stays on and I use it for downloading things using IDM
When I turn off my computer, I can still hear the CPU fan running. The hard disk turns off and my mouse light also turns off.
There is one other thing that happens after this. If I restart my computer, a message pops up from that IDM software. If I click "Install", it installs some files to my Windows directory in 2-3 seconds and after that an IDM icon appears. This usually doesn't happen after a normal restart. Maybe the IDM software consumes too much power and it causes the system to restart?
My computer is a desktop with a Pentium 4, 2 GB of RAM, and only a DVD-burner and hard drive attached.