Lost ability to login as user

I was trying to resolve a conflict while upgrading with apt-get. In the process I removed gdm2-2.4.1.6-92.ximian.8.5. I had tried XD2 for awhile, but had changed my session back to kde some time ago. I have tried changing my grom GDM to KDM and XDM, but can login to my user account only in failesafe mode to a dingle Xwindow. I can login to a KDE session as root, and I created a new user, which can login just fine as well. Seems I read in the past that something needed to be deleted in /tmp or something for a similar problem, but so far I haven't hit on the resolution. Mel