Monitor showing no signal in-game

hi

im new to this forum so i apologise before hand if its in the wrong section...

just recently ive been getting a problem with my monitor showing no signal, it occurs when i start up a game with high detail graphics, usually 3d games. (e.g. age of empires 3). The problem occurs after the game has reached the main menu and sometimes when i start the game itself. then it stops sending a signal to the monitor. its only when i play higher detailed games. ive looked around at similar problems on other forums and there has never been an actual solution as ive seen. my pc's specs are well within the requirements of the games, so im thinking maybe a fault with my hardware? or maybe a driver issue?

the screen is a samsung ls22pebsfviedc and the graphics card is an nvidia geforce 6600gt.

any help would be much appreciated,

many thanks,

tom