I just went through a week of pulling my hair out thinking the latest kernel/nvidia updates was screwing with my laptop. I started to suspect something other than that after trying all combinations of kernel/nvidia/nouveua/kernel params/bios updates. I ran across but still would get X lockups, kernel panicks, screwy graphics, NVRM Xid errors in the log, etc. I ran across these posts: http://en.community.dell.com/blogs/d...t-details.aspx
which started to confirm my theory that it was hardware. Fortunately my machine was still under hardware warranty will Dell, so I called in and reported the problem on wednesdat. After explaining all that I had done and that I knew about the hardware problem some of the dell laptops have had, the support person didn't pester me with questions like "did you try rebooting it" or ask anything about the OS. I just sort of left out that I was running linux and not windows.
The dell tech was onsite today (Friday) to replace the motherboard/gpu. He was done in less than an hour and didn't commented when I booted up and told him I was running linux. I've been running on the newest kernel (the one from updates-testing actually) and the newest NVIDIA driver from their site (185.18.36), with compiz and everything... so far so good! The nvidia chip has been running way cooler too, so I'm pretty sure it was hardware all along!