Recently I came across a computer that was getting a bluescreen every time it booted up unless it was booted into safe mode.  I traced the problem to a particular program but when I tried to uninstall it in safe mode, I was unabe to because the windows installer service is unavailable in safe mode by default.  The following commands will add the windows installer service back to your safe mode (with networking) session.  Just copy and paste them into the run-line:

REG ADD “HKLMSYSTEMCurrentControlSetControlSafeBootNetworkMSIServer” /VE /T REG_SZ /F /D “Service”

follow that with:

net start msiserver