Page scrolling issue

Hi guys,
This is a new one – all has been fine for the last month while working on my site but all of a sudden today I can’t scroll properly on any of the pages… really strange! And a little worrying…

Only seems to be an issue in Chrome.
I had an issue today where I added an incorrect css class to one of the menu items. This seemed to delete half of the menu and mess with the slider, which suddenly started fading all the elements out after 6 seconds (previously they had held static once they faded in).
So I re-added the menu items and fiddled with the animation setting of the slider (i.e. extended the animation of all elements to last for a full minute).
Could any of these actions have caused the problem?

Please help!

Chris