Need this fixing in a hurry if poss, please........

Office 2000. AMD 5000, MSI MS-7312, 4.0Gb RAM.

Word freezes the whole PC with a grey screen if opened after switching user. If the PC is shut down or restarted and then Word opened, no problem. The freeze will happen on any of the three users if switch user or log off/log on is used.
I have tried uninstalling/reinstalling and deleting Normal.dot.

Help...........