How did you try repairing/removing the Office installation (e.g. via Start > Windows Control Panel > Programs > Programs & Features > Microsoft Office (version) > Uninstall/Change)?
Have you checked whether Windows is trying to download & install the Win 10 'upgrade'? If it is, that can cause serious problems on some systems. You can eradicate an unwanted Win 10 'upgrade' using the GWX control panel:
http://ultimateoutsider.com/downloads/