Given the age of the PC, try the usual maintenance with canned air. Make sure the PC has nothing blocking the air flow on the vents.
Also, try DISABLE FLASH HARDWARE ACCELERATION (see google.)
I keep getting the blue screen of death over and over and over. It happens when I'm on facebook saving pictures.
My computer is an HP
Windows Vista 2007
Model # a6403w
Serial # 3CR8231KOG
System Product # KJ387AA-ABA