There are very easy tweaks you can make to prevent Firefox from showing ads, blinking text and marquees.
I tried posting the exact info for you here, but this board won't accept the code.
So you can look up the code yourself at
http://www.mozilla.org/support/firefox/tips#lay_adblocking , look about 2/3 of the way down the page under "Web Page Appearance", and include:,
Ad Blocking
and
Disable blinking elements
and
Disable marquee tags
You simply copy lines of code off that Firefox web page, using Notepad, and past it into your Firefox profile, which is on your computer in Program Files.
For each tweak, you "Save As" / "All Files" and give it the file names they tell you to use.
It's very easy.