My computer falls to sleep

Can anyone help.

My computer has recently been slipping into ‘Sleep Mode’, nothing can be done to ‘wake it up’.

It first happened when I was trying to play WoW, but now it does it at random times.

Also, when I turn my computer on, I should have a solid blue ring of light around the power button, but now it flashes with just under 1 second intervals.

When I force the computer off and on, I am told the system has recovered from a serious error.

STOP 0X000000EA THREAD_STUCK_IN_DEVICE_DRIVER (Q293078)

Thanks for any help.