By browser, do you mean homepage? Your browser is Firefox (I'm assuming because you're posting in Firefox help!); Google/MSN are webpages and not browsers. I'm going to work under the assumption you mean homepage. Method 1: Go to the top left and hit Firefox-->Options-->Options-->General Tab (first tab on left of window). There's a spot to write in the URL of what you want for your homepage. Type http://www.google.com. Hit ok. Exit FF, open again, and it should be Google. Method 2: Go to Google. Follow same instructions to get to the General Tab. Click "Use Current Page." Hit ok. Exit and re-open, it should be Google. Hope this helps.

Also see [[How to set the homepage]].