[airman]

To get into the Windows Vista Safe mode, as the computer is booting press and hold your "F8 Key" which should bring up the "Windows Advanced Options Menu" as shown below. Use your arrow keys to move to "Safe Mode" and press your Enter key.Choose Advanced Options for: Microsoft Windows Vista
Please select an option:

Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt

Enable Boot Logging
Enable low-resolution video (640x480)
Last Known Good Configuration (advanced)
Directory Services Restore Mode
Debugging Mode
Disable automatic restart on system failure
Disable Driver Signature Enforcment

Start Windows Normally Go into safe mode the first one and see if it starts plus you could also chose last know good configuration as an option.