Browser crashes while playing videos

Browser crashes while playing videos

"I have a new PC (HP dv6t with integrated graphic card) with windows 7 installed. When i watch videos (youtube, divx, etc) the browser eventualy crashes. It happens after some time (15-60minutes) and then happens within 5 minutes, untill I restart the computer. It happens with all brwosers (IE8, FireFox and Chrome). Also, when I open up the msn games, MSN crashes. I have already tried reinstaling flash and the problem still persists.
Any ideas?
thanks alot."