One or more of the initial setup files of MS office may have become corrupted when you re-installed the software. Either that or there were still files remaining after you uninstalled the first time and that it meaning that office cannot load correctly.

Search google for the MS office uninstall tool; this should successfully remove all files associated with office so that there are none left over and should also clean up any corrupted files. You will need to then install Office again; making sure that there are no interruptions during the installation to make sure no more files become corrupted