need help with browser

the problem im having is kind of hard to explain...basically the page on my web browser keeps bouncing up and down, this is on every page and it is very annoying...i think the problem started about the time i moved up to 1600x1200 desktop resolution even tho i still have the problem when i go back down...also, my primary browser is firefox, id prefer to stick with it if anyone knows a fix, the problem doesnt happen in internet explorer but i really dont want to use internet explorer if it can be helped

What happens when you try to scroll with the mousewheel? Does it scroll then stop bouncing?

nope, it continues to bounce

I don't know what happened to my system last night but I had a similar problem almost like my Z key was constantly held down so it would cycle through the page searching for Z. I tried to do a search and all the box had was Z's in it. I did a system retore to yesterday and it fixed it.