I use Firefox 3.0.6 and my homepage looks fine. When I look at it on IE 7.0.5730.13, the announcements are overlapping the right (fixed) column.

Why?

p.s. I should have added, this happens AFTER logging in.

It's your really long hyperlink:

http://www.microsoft.com/protect/products/computer/default.mspx.

There's no space in this link and therefore it cannot wrap. Firefox copes with it but IE does not. What you need to do is cut that link to your clipboard, and then type in some regular text instead and make that text clickable to the long hyperlink (i.e. the long hyperlink itself should no longer be showing, and only normal clickable verbiage). This will fix it.