Vista Fix
To fix the problem of windows vista giving you only a black screen and a mydocuments window after loading a profile, try this (I did this in Safe Mode):
CTRL + ALT + DEL keys to open the running processes. Open the file menu and try RUN. Now, type in REGEDIT.EXE to open up the registry and visit this key.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\
Find: "Shell" and check the value data. If it's anything more than "explorer.exe" change it to "explorer.exe" only.
Once you change the value to that only, reboot your machine and try to login. Hopefully, it's now restored and you have windows vista back.