Black screen of death or also know as KSoD has the following symptoms, after you type your logon password the computer loads and stops on black screen and the only thing that you are able to do is move the mouse cursor. The reason for this to happend is well know issue in windows logs files corruption.
To resolve the problem all you need to do is to rename windows Logs folder and create new one called Logs. How to do that:

1. You need an CD of any live distro of linux, hirens' boot cd ... etc. where you can mount windows partition. After you mount the windows partition of Vista go to %windir%/system32/winevt and rename Logs folder to Logs_OLD for exemple.

2. Create new folder and name it Logs.

3. Restart the computer and logon ot Vista normally.