Installation problem?

Last week, i refresh all the computers figure(70+ pc) & install new domain, that time i upgrated many things like service pack , firewall, antivirus,, etc, After some days, clients requested to install some more softwares like ACDC * office updation, when am trying to do all these on clients by all administrative rights, Im unable to do & recieving error message, even i have tried to install Ms-Office it is also showing error message hoewver i have the complete rights as administrator.
kindly give me some appropriate solution i would b able to work as gr8 excelleration.
It is windows 2000 network.