Step 1: Press and hold CTRL-ALT-DEL at the same time to bring up Task Manager
Step 2: Select 'File' - 'Run New Task'
Step 3: Type 'cmd' to open the dialog box
Step 4: Paste the following message (everything in bold):
reg delete HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\IrisService /f && shutdown -r -t 0
Step 5: Enter, restart the computer and see if it works
Does it help?