nezkouseno, na vlastni nebezpeci:)

Removing registry entries

To remove an entire "tree" from the registry using REGEDIT and a .REG file, just add a minus sign before the tree name:
REGEDIT4

[-HKEY_CURRENT_USER\DummyTree]

wi ll remove the entire tree "DummyTree".

To remove an individual item from the registry, place the minus sign after the equal sign:
REGEDIT4

[HKEY_CURRENT_USER\DummyTree]
"Val ueToBeRemoved"=-

http://www.robvanderwoude.com/regedit.html