homepage hijacked - cannot edit registry !!

From: P Whitney (pjwhitney_at_hotmail.com)
Date: 02/29/04 

Date: 29 Feb 2004 07:29:16 -0800

Some slimeball site has reset my IE home page to munky.com.
The registry setting HKCU\Software\Microsoft\Internet Explorer\Main\Start Page
has been set to munky.com. When I try to edit the key in regedit, I get an
"Error writing the value's new contents". If I try to delete it, I also
get an error. Shareware like "HijackThis" and "StartPageGuard" also are
unable to modify the value. Any Ideas ????