2 problems with MS Office XP Professional

[Steven]

I continually get a 'preparing to install' message every
time I navigate from one program to another. I cannot
download updates becasue i get a message saying
components are missing.

second problem, I want to remove the 'on behalf of'
message that is going out on every email tht I send.
This started when the computer user changed, now it
appears that me, the new user, is sending everything on
behalf of the old user. I have no delegates tab as the
ms assistant refers me to.

Thanks!!!