msn messenger

From: Diane (didzmo_at_aol.com)
Date: 01/22/05 

Date: Fri, 21 Jan 2005 17:33:06 -0800

I removed msn messenger 6.2 in error from add/remove
programs. It has reverted to version 4.7 now. On trying
to download 6.2 again I receive fatal error 1603.

I then tries to remove all messenger from XP by running
Dll32advpack...... and received error "Advanced INF
failure reason Access is denied"

Not sure what I have done or how to upgrade again. Any
help would be greatly appreciated.