MacBook Pro goes straight to sleep mode and doesn't start until i fry... Somebody help !!!

Greetings !!

I have MacBook Pro 4,1, 17-Inch, Early 2008. I have been using this mac since 2010 and it was perfect, never had any serious problem.

Recently, it has started this strange problem. It works fine for shutdown and stops working if i restart/sleep/close the lid. It goes straight to sleep mode and doesn't start.

Once it goes to sleep mode, there is no way of waking up. The same problem happens if i "Restart" the computer, or close the lid. It doesn't turn on, it shows black screen, no chime sound, no keyboard light. Only fan and DVD get the power i suppose. Every time i will have to "shutdown" the computer properly, otherwise it won't start next time. So, now the question is how do turn the mac on next time ??

Well, i leave it for 2/3 hours, then it heats up like ****... and then i press the power button, and it turns on again. Again it works until i click "restart" or it goes to sleep mode. I know it could be the well-known nVidia problem that early mac 2008 has. But Apple Store said it doesn't have any nVidia problem, also it doesn't have that warranty period to change the logic board.

What kind of problem is this, that works fine for shutdown and stops working if i restart/sleep/close the lid ???

And every time it has this problem i need to fry my laptop !!!

Anybody, any help will be appreciated.