NT Workstation keeps rebooting

Norton Antivirus was locking up the NT 4.0 workstation so I uninstalled it and the workstation worked just fine untill the next day. When I turned it on the next day it would not allow me to logon on, it was stuck on the logon screen. I did a repairwith the emergency repair diskette and now it just keeps rebooting itself. How can I get my workstation to work again.