I found out about this NVIDIA GPU issue from buying a Dell D620 off Craigs List for $100. It was listed as having a video problem and the poster thought it needed a new LCD display or an inverter. Since it had 4gb of RAM, a T7600 processor, bluetooth and was in pristine condition, I took a chance on it since replacing and LCD/invertor is simple. Then I started researching it and came to the conclusion it was the NVIDIA GPU and not the screen. I thought about doing the repair myself, and probably would have if the laptop wasn't so nice, but resoldering a chip was more than I wanted to take on. Then I found this repair shop in MA and for a flat fee they will fix any number of problems. If they can't then they refund your money in full and ship the laptop back or give you a new quote to cover the repair if it needs a new screen, motherboard etc. Since the $90 included return shipping, and they replace the GPU with a new one, it seems like a pretty good deal. Plus, it eliminates the chance I would have trashed the laptop beyond repair. Then the fact they shipped the laptop back to me in one week of receiving it was just icing on the proverbial cake.
So now I have a very nice laptop with great specs for less than $200. You gotta love the things you can find on Craigs List.