Both of the blue screen crashes have happened while using the internet and no crashes have been experienced when playing games.
I installed a new Ati HD5670 graphic card a couple of weeks ago and the pc has been running fine up until now. I also made sure to uninstall the old Nvidia display drivers, before installing the new card and Ati drivers.
I have used WinDbg to view the crash dump file and i seems to be memory related by a driver incompatibility, but i am not sure as i am no tech expert.
I hope i can get some expert help here, to figure out what is causing these crashes.
I have attached the minidump file.