Flash problems (Complete system crash)

Hi,

Im trying to watch hour+ long flash videos on youtube. Im able to watch the first 45 mins to an hour and then I get the dreaded Blue Screen Of Death. I though that this was because my temp folder was filling up my HD as I have windows XP running on a six gig so I moved my temp folders to my larger 120gb hard drive, however I still get the same message. Does anyone know why this is.

Thank you,

LTumbleweed