there are several things with office xp which can lead to such behavior:
When you install office just default some items are only installed 'on first use' so to prevent that
make sure that when you install office you use the customized setup and set all the needed options to 'run from my computer'
If needed install servicepacks etc.
If this doesn't resolve the question you could tweak the default user profile:
Make a test account (with the same rights as you're normal users)
Log on with test account and run office (e.g. word)
Sometimes (especially when servicepacks are installed) it will ask for the office cd-rom.
After you have succesfully started office xp log off and log on as an administrator.
Now go to 'c:\documents and settings\Default user' and copy ntuser.dat and ntuser.dat.log to a save spot
Copy the ntuser.dat and ntuser.dat.log from the testaccount over to the default user ones
Now remove the total directory 'c:\document and settings\<test user>
Try to log on as the test user and see if all works fine (i know that sometimes the quicklaunch bar is not updated )
Tweak the profile of the default user until you are satisfied by doing the 'loop' of copying ntuser.dat/delete testaccount profile/log on as testuser/tweak/log off/
After you are satisfied remember to delete the testaccount (not only the profile, but also the loginaccount)
You can always uninstall office, copy the contents of the cd to your hard drive. Something like,
Install from there, not the cd. Take the cd out. Do that on each machine. Now everytime it needs the cd it'll look under c:\officecd instead of d:\ or whatever your cdrom drive is, so it won't even need the cd for it.
There's a setting in the registry you could change, but not sure where it's at. If you look for it, it'll say something like installpath d:\
Just change d:\ to c:\officecd or where ever you copied the office cd to, and it won't ask for the cd anymore, because it'll just copy whatever it needs from your c:\officecd path.