[Margaret Pilkington]

It was like that for me a few weeks ago.
It worried me a bit. I thought that the machine had picked up something nasty(although, I would have been surprised as the antivirus I use is spot on)...anyway I ran a big scan, nothing showed up.

I had been getting alerts that my browser was out of date and urged to update to IE9.........and I did this.....things ran faster and much more smoothly, but I was impressed with IE9.......was advised to convert to Firefox as a browser.
Since then...much much better. Faster, smoother and with fewer bugs.

I know this won't much help your query Cashy, as you were one of the peeople who advised Firefox......so I assume that is what you are currently using.
Maybe you need to upgrade to a newer version.
What do I know?(Not a lot).