Keyboard shortcuts disabled in Mountain Lion

I'm using an iMac with Mountain Lion. I have a wireless keyboard and trackpad. Last night I went out and when I came back my cat had been on my desk, knocking things over. Since then, my keyboard shortcuts all seem to be disabled.

I use Word for my work, and I have tried, unsuccessfully, to use the following shortcuts, as I do everyday:

cmd+z
cmd+i
cmd+b
cmd+s
cmd+shift+s

cmd+a

cmd+c

cmd+v

(I also tried a, c and v online. All it does is type the letter 'a' or 's' etc)

Also, cmd+shift+3 / 4 to take screenshots are also disabled, so it isn't just in Word.

I have absolutely no idea how they have suddenly turned off and presume my cat inadvertently clicked a combination of buttons that has done this. Is there a keyboard shortcut to enable/disable them?

I went to system preferences > keyboard > keyboard shortcuts and none of them are even listed there, but as they are universal shortcuts I don't know if they ever were.