Just use the ZOOM feature in the lower-right corner of the window in IE7. It works even better than your Firefox screen, because it enlarges everything, not just the fonts, so everything stays in proportion.

Great!   I have that ZOOM feature and never thought of using it before. Thanks for the tip!!

Todd
Yes, that is another way to go about it.
If that wasn't there, there are also some programs that magnify what ever you want to on the desktop, not just what is on the browser.
Those programs might be a little hard to use due to their nature and what they have to do.
But they can help a lot if you have bad sight, a search engine is needed to look for them.

That Zoom might be the best thing for the Web, but for other uses there is the Magnifier that comes with Windows that is on Accessibility, but I found a freeware magnifier program that I like better than that one called:
Zoom+ and also called ZoomPlus, for those who need it off the web for Pc work, it is here:
http://www.onlythebestfreeware.com/program.asp?program_id=86
And download here:
http://www.onlythebestfreeware.com/out.asp?url=http://www.gipsysoft.com/zoomplus/zoomplus.zip