Hi guys, I'm not usually one to ask about this kind of thing but it has me stumped.

When my Firefox opens, it loads my homepage as normal but the address bar has nothing in it. I can navigate to other pages by typing in addresses as usual but the address I type stays there even if I follow a link to another page. My Back button has also stopped working, yet pressing Backspace to go back works fine.

This is on a 2 day old Vista Premium laptop and Avast and Spybot checks have come up clean. There are no suspicious system processes running and I run NoScript so I don't see how any Javascript-based nasties could have got in.

I'd be grateful if anyone could please shed some light on the cause as Googling hasnt helped- is it simply an error or a sign of more serious malware?

EDIT: Sorry guys, I found the cause- the bloody Polar Rose plugin had gone wrong.

Have you had any system crashes whilst FF was open? Some versions of Firefox are particularly prone to corruption of browser settings (which can result in problems like this) on system crash.