Notepad Virus?

Today I was hit with a virus that replaced notepad.exe with another file and screwed up Internet Explorer's default actions. Basically, there were 3 symptoms

* Anytime Internet Explorer opens a new window, a Search panel opens pointing a spam oriented search engine - www.i--search.com
* When you double click an *.txt file, notepad.exe is supposed to run - I suspected a problem when nothing happened.
* I normally edit html files by viewing them in Internet Explorer, right clicking, and selecting View Source - Nothing happened.

Any ideas? :/ I'm running a virus scan right now, but I doubt it will find anything.

This might help.

http://www.sss.ca/se...c9?OpenDocument

Thanks. This virus didn't rename anything though. :/ I still have Notepad.exe where it originally was. Thanks though.