Three finger swiping

Hello all,

2011 MBP was working fine earlier today. Put the lid down and have just come back to use it after about 10 hours. Since this I have lost the ability to swipe between my different desktops, and the Expose feature. I have rebooted but this hasnt really helped. I had a quick Google but all I could find really was issues similar after upgrading to SL in 09. If I try my 3 finger swipe whilst I have Chrome open it just recognizes it as a two finger swipe and goes back a page.
Does anyone have any suggestions please?
Thanks

Chris

Right, I feel a tool. Just went over all my settings again and realised that the settings had changed to perform the functions using 4, instead of 4 fingers. Does anyone have any ideas as to why it may have changed these settings by itself?
Thanks

Chris

Did you turn on three finger drag just before swipe changed to four fingers? I just did the same thing.

If you look, I'll bet three finger drag is off. If you turn it on, swipe between full-screen apps will switch back to four fingers.