Stop error Session3_initialization_error when running setup

Does anyone know what would cause a session3 error as soon as everything is
loaded, just as it says "Setup is starting windows" before it gets to the
menu?

I need to run the setup from the CD, but whenever I get this error.

I was trying to do a new install over an existing win 2000 OS, but I can't
even get to the setup menu. I tried doing an install from inside windows
2000, but it won't let me delete the partition. I went ahead and formatted
the partition using Partition magic, so now it's boot from CD or floppy only.