Try going to the Options menu, then select Global Restrictions (or Circuit Restrictions? -try both)... if you see a prompt for a password the default is "testbench" and I guess that your options are all going to be disabled... re-enable them.
If that does not works then go to your installation directory path, and from the Users folder delete your configuration file (make a backup copy first -just in case)... restart Multisim it will recreate that file.
Thank you Nestor, I am back in business.!!
Going to "Global Restrictions" and entering "Testbench" as you said,did the trick..
It presnted me with a dialog box showing a list of tool bars which were all cheked "disabled".
I unclicked all the check marks and now everything.works ok.