Why does my computer not turn on after a successful shut down?

[vinayak_11]

I am using a pc with following details
Duel core 3.0 Mhz processor
Intel dg41rq original motherboard
4GB RAM(two sticks)
500GB HDD
OS Win7
The problem is that my pc starts normally after working( for about more than 20 mins.) when I shut down pc and immidiatly try to start it again it does not starts and it producess the beep sound continueously.
then I turn off power. After a long break( for about more than an hour) the pc starts again normally. and again when
I shut it down the same things happens again.
Recently I have replaced the motherboard. I also had increased the RAM from 2GB to 4Gb.
Please tell me what is the reason.
vinayak.kdm81@googlemail.com

 

[trapper]

Try doing a windows repair. Take your windows 7 DVD or the recovery disk that came with your PC (if it was store bought) and run the repair tool off that, see if that fixes anything.

 

[vinayak_11]

thanks trapper

 

[carl 21]

i had the same issue it was my hard drive some times it will work and some times it will not i put a new hard drive in and now dont get the issue no more try a different hard drive