Ok, I've played SL for a good few years now and lately I was starting to go a little nuts. The SecondLife client would crash at the worst times, usually while I was building or terraforming. Every time it would crash I'd get a C++ Runtime Error and Vista would tell me it saved my system from a crash, no thanks to the nvidia video card drivers. I assumed it was an issue with SL & Vista until the other day I decided to touch my video card while the PC was running. I've done this before and it has always been warm, but this was beyond that. A quick touch burned and told me something was wrong with the cooling.
So luckily, after disassembling the video cards cooling so I could get the dust bunnies out, I've not had a single crash and SL is performing better then ever. Now if LL can just get the grid back up I could get back to work.
*edit* as I wrote this the grid came back up. YAY!