system shutdown on boot up(logon process system terminated unexcpectedly)

i just upgraded 98 to w2k pro. it was working fine for a
couple of days. after i installed a couple of printer
drivers today, norton anti-virus, link sys (print server)
software, after the statrting windows 2000 screen, the
screen goes blue then an error "the windows logon process
system terminated unexpectedly c0000021a system
shutdown" and it auto reboots and gets into the loop -
error, reboot, etc. Help...
I created setup disks, went into the recovery mode but
just get a dos prompt - don't know what to do with this!
Please help!!!!