Under the advanced options, there's an option to "restore browser defaults". This will correct any possibly browser hijacking to the original windows defaults. The windows default homepage is, of course, msn.com

To change this there is a button on the right that says "Change my restore default homepage", where you can put your desired default homepage the next time MS Antispyware runs.

Hope that helps!

Oh, and to all the anti-MS haters, perhaps next time you should look at the options that are directly in front of you, or perhaps learn to understand what the programs that you're installing do.