I am not sure if this is right or not, but was wondering if it is an upgrade of Office? Upgrades have to have a Office program already installed to be able to install.

If you try installing an upgrade it will put some Office code on your PC, but wont finish installing because it couldnt find a version of Office. Then when you try to install the trial version it runs into the code from the upgrade, and cant install because of that code being there.

Hope this isnt too confusing.

Go into the uninstall/install program area in the control panel, and see if there is any microsoft office in there and delete/uninstall anything you find with the words microsoft office. Then go look in your program files by exploring the C drive, and find any microsoft office files and delete them.

Once you clean all the files off that you can find, then try and install the trial version again, then the try using the disc. It should then load properly.

If it is a upgrade version of Office that you have, go back to where you bought it, and request that they give you a full version. Usually the full versions cost a bit more than an upgrade. If you get the full version it wouldnt matter about the Office files in your PC, because the full version will find them, and then ask you if you want to delete previous versions of Office. Once it deletes the files it will complete the new installation.

I am not sure if this is the problem you are having, but it is one I run into fairly often. Especially with microsoft operating systems.