If you have a valid Product key for Office you can download the software, someone here should be able to provide a link to download from. Please state what version of office you have.
Once you download the correct version associated with your product key, just install and use the key.
Found this for Office 2010
If you purchased an Office 2010 Product Key Card and don’t have Office 2010 preloaded on your PC, you can download the software. Do the following:
Locate your 25-character Product Key. You must have a valid Office 2010 Product Key to install and activate your downloaded software.
Return to http://office.microsoft.com/en.....A101847520
Follow the steps online to download and install Office 2010.
P.S. once you get OS and all apps installed, i would recommend creating an image of the hard drive, saves so much time if you need to rebuild!!!!