Send the card back to the manufacturer for repairs if the warranty is valid. This procedure will void your warranty.
Check to see if your warranty is valid. This can be done by looking up the serial number of your graphics card for retail cards in most situations. For OEM video cards, the warranty is tied to the system and may expire sooner then a retail card.
Experiment with lower heats first, and increase temperature as necessary.
If you've already finished this guide once and are baking again, increase the temperature slightly - 395F (200C) or 400F (205C).
Most of these temporary repairs only consist of the expanding/shrinking of bumps under the surface mount of the graphics chip. Therefore, a lower heat may work as well.
Insert and tighten all the screws carefully. They are quite small, and the PCB may be damaged if the screws are over tightened.
Tighten the screws in an alternating pattern. E.G. Top left, Bottom right, Top right, Bottom left. With more than 4 screws, use a "Star" pattern when tightening the screws ensuring all screws are evenly tightened.
I also fixed a almost dead NVIDIA 512mb MXM II card, at the first point I put the card 8 min to 190ºC aprox, it improved the performance but not yet to run.
Then i repeated the operation with 205ºC and 10 min and the card ran perfectly, add some thermal paste and it's solved.
I just finished doing this with an evga gtx460 i got from a friend of mine. It was throwing up artifacts and crashing constantly before. Now it's stable for over 10 minutes. It looks like it's fixed but only time will tell. Wish me luck and thanks for the guide!