User get black screen when trying to login

Hi All,

I logged into a computer as an administrator to install an application client, citrix client, on a users computer. The installation went successfully and worked fine on the administrator account, however, when the user try to login in to the computer the computer goes black screen after welcome message and stay black until it gets shutdown manually. Nothing works in this state of black screen, ctrl+alt+del etc doesn't work, although the mouse cursor is visible and movable - thats it.

Technicals;

1. Windows 7 Pro 64 bit OEM / HP probook.
2. The user has administrator privilieges.
3. The user can login in safe mode, but a restore to a previous restore point didn't work.
4. sfc /scannow completes without any errors.
5. Windows update doesn't work in users safe mode with network. Shouldn't it supposed to be working?
6. Tried Prevx fix for black screen / explorer not running.
7. User is on company AD domain so i need the user account to be working again.
8. Disabling all startup programs doesn't help.
9. Administrator account works fine with normal login / drivers loaded etc.

Any suggestions on how to either fix the problem or get the user account to work again?

Thank you!

Nicolai