Raven,
There are a LOT of entries in the Registry! I can't recall whether they are UltraHal or Zabaware so check for both if you venture into those woods.

A regular registry cleaner won't clean them either. You will / would need to do a manual search and destroy operation if you so choose.
Start button > type 'Regedit' > Enter
Make sure the word Computer is selected instead of somewhere deep within the registry.
From text menu select Edit > Find > TYPE the word 'zabaware' and press Enter
After it finds a hit, do what you feel you must.
Next Press F3 to search the same word again but deeper into the registry.
Good luck and be very careful playing in the registry as you can screw up your whole computer. Make a backup first.