Bet U cant solve this!!!!

Pc config:
Intel core 2 duo e6750
Intel P35 chipset , DP35DP
2 gb ram
160 gb sata hdd
nvidia 7600gs graphics card
windows xp pro sp3

The problem i m having is quite unique, Its that every time i start my PC after a interval of 7-8 hrs, I don't get display on my monitor. I have to keep pressing the power button 15-20 times again and again after which i get display on my monitor. since i don't have on board display, its hard to find where the actual problem lies, is it with motherboard or graphics card. Also once i get a display on my monitor then even if shutdown at that moment and again start my PC by pressing power ON button(once) i get display on my monitor. i had recently changed my SMPS and crt monitor, but the display problem persisted at that time also. plz help