User Menu Problem in Ubuntu 12.04

[webusr1]

All,
I installed 32-bit Ubuntu 12.04.2 (CD install) on my Dell Inspiron 1420 laptop and I have ONLY one problem. When I click on the "User Menu" which allows me to switch between different users, after two users are selected then the system locks up at the login screen. On the third user I'm locked, and I have to reboot the system to exit the login menu. Note that I don't have this problem another Dell laptop (CD install) and another Dell Desktop (upgraded 10.04 to 12.04 online) with Ubuntu 12.02. Everthing else works great, and the performance for this old laptop is great with 4GB RAM,

How do I troubleshoot this problem? Any help will be greatly appreciated.

Thanks!

[dino99]

i suppose you might find something usefull into the logs; glance at xsession-errors first.