Encountered a blue screen of death (BSOD) on Vista SP1 computer the other day. It wasn't a virus; wasn't a corrupted OS; wasn't a hardware problem. The specific error was on mrtRate.sys.
It was a conflict with Quicken 2002 and Vista -- which had been working fine for about six months. Solution: Start in Safe Mode. Go into Hardware Devices -> Show Hidden Devices -> Non-Plug and Play Devices -> mrtRate. Go to Driver Tab -> Stop driver. Set Startup Type to "Disabled".
System should then start up without a hitch.
Note: mrtRate does not seem to be used for anything else (with maybe one exception) - and latest versions of Quicken do not use it -- so, at least in theory, if you upgrade Quicken, you should be fine.