In addition to resetting the keyboard shortcuts to the defaults as aaishimshir suggested, you could check the Mac OS keyboard shortcuts. Make sure that none of the Adobe shortcuts are the same as any of the Mac OS shortcuts. If so, the Mac OS shortcuts can interfere with the Adobe shortcuts.
Thank you but im afraid no succes....
Somehow i am not able to use options like Liquify because the cursor stays a 'hand' and doesn;t show the brush....
And i can't 'grap' the image to move around
It sounds like the installation may be corrupt. You could try resetting preferences. Preferences in Photoshop
If that doesn't work you'll need the CC Cleaner Tool. Use the Creative Cloud Cleaner Tool to solve installation problems