if you are facing black screen problem in Vista just follow these steps
In safe mode, go to start->run, type in msconfig, and the system configuration window will come up.
First, try clicking on startup and say disable all, then say apply. Try restarting your computer and loading it normally, and see if it lets you get anywhere. If it does, you can go back into msconfig and start enabling startup items again until you find the one that is messing you up.
If that didn't work, try going back into msconfig, keep all the startup items disabled, and click on the services tab. check the box saying hide all microsoft services, then click on disable all, and hit apply. Try restarting into Windows normally again, if it works, then again, you have to figure out which service/startup items are affecting your boot up.
If that didn't work either, then you may have a graphics card issue. Where does it stop when you try to load Windows normally?