|Have you tried hitting Ctrl + Shift + Esc to open task manager?|
Sorry re-read your post... the above probably won't work.
Follow the link below and run the script on the right hand side of the page... line 51
Enable the Task Manager
Be sure to click Enable, not the other.
Save the .reg file to the desktop, once downloaded double click to run then allow the merge.
Let us know how this works out.