Noob question, graphic problems due to power supply?

Hi All -

I recently replaced my power supply in my Alienware PC due to it dying on me. I purchased what I think is a fairly decent power supply (PSU APEVIA(ASP)|ATX-CW500WP4). My old power supply was a mear 340 watts, and this one is 500. So here's the problem. When playing games that consume alot of resources, i.e. graphic intense games etc... I get abrupt terminations and have even had sudden re-boots. I have read that this could be a sign of a power supply problem.. But, the computer seems to work just fine with all other applications, i.e. surfing the web. I was wondering if there was something in the BIOS that I need to change because of the new supply? The only other thing that I noticed was that it takes a little while longer than normal to boot up compared to with my original supply.

Any help would be greatly appreciated!

thanks,
Kev

Will do. thanks again