I does not sound good. You could try removing the battery for a few minutes and then try again, also disconnect any external leads that you have plugged in and take out the DVD drive. After that, you should check the warrenty.
It could be a motherboard fault but it could also be memory or a poor conection somewhere. Another thing that you could try is removing the hard disk and see what happens. Obviously it will not boot if you do that but if it got past the initial boot it would sugest a disk problem.
The other thing to check is is the fan running.
As a last resort, you could try leaving it in the fridge overnight.
If the fan is not runnng then you need tosort that first. Can you turn the fan by hand? Is it solid with dust?
If you can unplug it, put a voltmeter on the motherboard socket. Be careful not to damage anything, you are really at the stage where youshould take it to the repair shop.
My coment regarding the fridge was based on the hope that thermal change can sometimes bring electronics back to life. I've been lucky with hard disks using this method although they ar partly mechanical. Leaving in fridge does have it's dangers though hence it is a last resort. You have found one fault, so I would sort that first.
Sorry Breydon, had to go out.
Sounds like a hardware fault, not a software one.
Somebody with electronic diagnostics needs to have a look, imo.
P.C.s are relatively easy to fiddle with, but laptops are tricky.
If the fan is not cooling the main processor, then the software should boot up & then shut down & continue doing this, in my experience. Hope it isn't one you bought in a pub!!!