Check to make sure you are not using custom shortcuts. Set your shortcuts to CS6 and try again.
Hi I tried that, its the same, it just doesnt work!!! thank you for your suggestion x
Have you tried searching for Cut in the Keyboard Shortcuts dialog? Perhaps is somehow got assigned to a new command.
you may also want to try deleting your preferences. Hold down Option+Shift when launching Premiere.
according to keyboard set up it is in the edit section under cut still. I tried this resetting everything and it doesnt work either, cmd z works fine undo, just not cmd x for cut, any other suggestions please? its very annoying!! Thanks x