Deletes the value value_name in the Registry key keypath.
If keypath or value_name contain spaces, enclose them in quotes.
keypath is the full path to the key containing the value. You can abbreviate HKEY_LOCAL_MACHINE to HKLM and HKEY_CURRENT_USER to HKCU.
Example:
This example deletes Myval in the named Registry key.
REG DELVAL HKEY_CURRENT_USER\Software\Netscape\MyKey MyVal