My System:

Windows XP Professional 32bit
AMD Athlon XP2200+ 1.81GHz
704MB RAM
SiS 661FX_760_741_M661FX_M760_M741 (SiS 6330)

This bug occurs in EVERY 2.5x version of Blender.
When i go to File > User Preferences it opens a grey window where the Preferences should show but instead of that
Blender Freezes for a secon and i get an "Visual Studio Just-In-Time Debugger" error

"An unhandled win32 exception occured in blender.exe [1720]. Just-In-Time debugging this exception failed with the following error: No installed debugger has Just-In-Time debugging enabled. In Visual Studio, Just in time debugging can be enabled from Tools/Options/Debugging/Just-In-Time.

Check the documentation index for 'Just-In-Time debugging, errors' for more information."

As a workaround i change the 3d Viewport to userpreferences and then it works.