I have the same problem, started a couple days ago. SL will run fine but if I logout or crash then when I try to restart it says "Detecting hardware" then in about 5 seconds I get the Windows dialog telling me "Second life has stopped working", Windows is checking for a solution. If I then run the latetest installation file, without uninstalling, SL will load and run fine. But when I quit or crash again the same thing happens. It's like it runs only once and then I have to run the install again. I have tried uninstall and reinstall several times, same results. I tried to do a complete and utter removal of all SL files after uninstalling and got the same results. Maybe something in the Registry or some other file I missed, but this is clearly a bug. I've been in SL over 2 years and never had this problem. Maybe something in Vista contributing to the problem, don't know. I'm going to open a ticket see if LL can help.
As an IT person I just wanted to shed a little more light on this as I expect more people will encounter this problem. I will post any updates.