I understand that you can change it back every time something replaces it? (I'm making sure, because I had a virus a few weeks ago that prevented me from doing that -- I got rid of it quickly, though

).
You need a program that won't let anyone change your settings. I just know of one that won't anyone change your home page, but it's a commercial product. ($34). I've tried it, and it's really very good. It's called "Security Administrator", here's a link:
http://www.softheap.com/secagent.html
Here's a link to a more pricey program ($49), "1st Security Agent":
http://www.softheap.com/newadmin.html
(You can try them both for free). I've tried this one, too, and it was great. I didn't remember if it had the option to disable changing the home page, but I Googled it, and it seems that it does:
http://www.softheap.com/security-faq/disable_changing_home.html
But they only work on Windows. Btw, if you have Windows XP, there might be a way to disable changing the home page in there. Read this (to know where to find it, please note that you'd have to
enable the "Disable changing home page settings", not
disable it, the guy from the discussion was looking for the opposite of what you want to do):
http://www.experts-exchange.com/Applications/Q_20660348.html
http://www.experts-exchange.com/Operating_Systems/WinXP/Q_20639532.html
I've found a cheaper program that also does it ($19,90):
http://www.history-cleaner.com/
Hopefully something of that will be useful to you.
