Problem logging in after migration from Mountain Lion to Snow Leopard

MacPro had OSX Mountain Lion.

Time Machined that sucker.

Reformatted, installed Snow Leopard. Boom.

SYSTEM RESTORE (not Migration Assistant) User, apps, settings, files during the install process.

Everything seems to work, aside from Lion specific apps like Face Time.

Did a software update, a bunch of stuff, forgot exactly what.

After the restart for the software update- ran into a problem.

On the log in screen. Type in my password, seems to register, screen turns blue, spinning wheel, flash, back to log in screen.

Verbose, Safe mode, resetting user settings- all that- nothing works. Any ideas what may be wrong?