I have an E1705 from 2006 and my NVIDIA GO 7800 failed 3 months after my 3 yr extended warranty expired.
Diagnostics showed damaged video memory on the NVIDIA card. After much research, it appears clear that the NVIDIA card failed due to overheating. There are a few stories posted stating that Dell and NVIDIA were aware of the overheating problem and there was supposed to be a driver fix released that would turn on the GPU fan earlier, but no such driver fix was ever released for my E1705 before the NVIDIA card failed (current drivers for E1705 on the Dell support site are the same drivers that shipped with my laptop in 2006).
There are a few discussions online about putting video cards in the oven to remelt the solder and solve problems due to cracked solder on the card, but I was too afraid to try.
Finally, I replaced the NVIDIA card two weeks ago with a used ATI Radeon Mobility X1400 bought on eBay for $239 and so far no problems. Dell posts easy to follow instructions for replacing the video card.
When choosing my build of the E1705, the NVIDIA GO 7800 was advertised as the "gamers" option and my older 3D games run noticeably slower with the ATI X1400, but routine Office tasks and browsing show no difference.
Important note: I also downloaded the "I8kfanGUI" program so that I could force the fans on the CPU and GPU to HIGH and monitor the GPU temperature (both fans on high keep the GPU at around 35C while doing normal Office tasks). If I had known that the NVIDIA card was prone to overheating, I would have done this before failure.
I had purchased my E1705 with a 3yr extended warranty with the idea that I would replace the laptop around that time, so, overall, I am happy that I could fix this problem for far less than the cost of a new laptop; I will, however, be wary of buying another laptop with a "high-end" graphics card. Perhaps the compact infrastructure of laptops are inherently ill-suited to handle the heat dissapation requirements of a high-end graphics card?