Alot

This reminds me of years ago when I inadvertently added yahoo toolbar to my browser. I remember not being able to remove it via add/remove option, but I did find a way to disable it.

If all else fails, you could uninstall then reinstall your browser...

Looked up a possible option real quick...

While in browser, click VIEW
Click TOOLBARS
Unselect ALOT

I performed each of your steps, but Alot came back.

Hmm... after you tried those steps, try resetting google.com as your homepage:
On your browser, go to google.com
Click TOOLS
Select OPTIONS
Click USE CURRENT PAGE
Click OK

worth a shot...

I remember a time when I tried to change my home page from yahoo to something else. Yahoo kept hijacking me. Later versions of Explorer allow you to prohibit home page hijacking.