Windows Vista desktop display missing

I am having problems with my computer not showing the desktop. It is just black with the curser. I can switch to another user and it will display. I have tried to restore to another date and it doesn't help, it is still black when it reboots. If I go to task manager I can get it to show up again if I load explorer.exe, but a lot of things still won't open. Security won't work and I can't get into networks. Please help!

 

This problem is usually caused by "˜malware’, so run your "˜anti‘ programs.

If it’s not malware, try this:
Click the Windows Orb (Start), type regedit, press Enter and navigate to registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon. In the right pane, make sure there is a REG_SZ named Shell and it has a value of "explorer.exe" (no quotation marks). If it’s not there, create it by clicking Edit > New > String Value then right-click it and key in explorer.exe then restart the computer.

If the Windows Orb (Start) is missing, open regedit via Task Manager by pressing Ctrl+Shift+Esc then on the Applications Tab click "˜New Task’ at the bottom, type regedit.exe and press Enter.

To be prudent, create a system restore point (rstrui.exe in Task Manager) before making any changes to the registry.

 

OK I tried to run regedit in task manager and it just freezes up and stops responding.