Don't Know What's Wrong...

Everytime I run any game with intense graphics like NBA Live 2005 or FS9, my monitor just goes blank after a little while. My machine stay's on, but my monitor just goes blank. Nothing can make the screen come back on except manually restarting. See my system spec's below in my Sig...I don't know what's wrong...it just goes black and my monitor says "Entering Sleep Mode".....What's going on?? My video card is brand new and I only got it about 3 months ago. The only thing that is worrying me is the temperature...it usually stays around at 88 Degrees Celcius....but that's partly because it's damn hot here. The weather is thankfully changing now and it's becoming cooler....maybe that's it? Or my power supply....I am not sure which it is....could it be both...or has my card finally died? Keep in mind that my comp stays on 24/7....I am stopping that habit now because my computer is over a year old now...
Thanks in advance for Help!!!
Ashar

Thanks in advance for Help!!!
Ashar

