Cannot login after updates installed

I have a Compaq Presario 2500 notebook running XP SP2. Today it decided to do an automatic update and installed the .NET framework service pack and some kind of GDI upgrade. After reboot the XP splash screen appears but the login does not. I tried doing things like safe mode, last known good config, etc. No luck.
I am on the road and in serious need of this laptop. Help appreciated.