What was it that told you to remove this key?
Have you tried System Restore to just before you deleted this key?
If that fails see if you can find the software and drivers from here;
http://h10025.www1.hp.com/ewfrf/wc/product?cc=uk&lc=en&dlc=en&product=303753
Make sure you reboot the system before trying to install that software.
Mark
I had a virus and part of the cure was deleting a registry key. When I re-booted, I had a message that I had uninstalled the HP printer in a dialog box.
The program was still installed but I could not access it. I uninstalled all HP components and then tried the CD I had originally installed it with (actually a replacement CD installation disc). It is like Windows is unable to understand or create a link to the installation. I even downloaded HP's newest updated version and the same thing happened. The key I deleted is: HKEY_LOCAL_MACHINE\system\currentcontrolset\Services\83d704e
Any help would be very useful.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic