|The problem is hardware related. It is down to a manufacturing fault with the geforce 8400 and 8600 series of cards from nvidia, both desktop and laptop. |
The problem also affects the dv2000 and dv9000 series laptops. the problem starts to appear roughly 3-4 years into its life, when the solder on the card starts to become defective due to heat. If you want a temp fix, applying a heat gun to the graphics card (no more than 15 secs, making sure the heat is applied directly only to the chip) would solve the problem for a short space of time. A more permanent solution would be for you to have someone do a complete reball of the chip and reapply fresh solder.
I hope this helps.