I would reccomend reonstalling everything from scratch. First though you shouldnprobably run boot and nuke on the HDD. If you leagally bought office last time but no longer have the disc, you should be leagally (depending on where you live) to download another copy of it. The thing is though is that you get one copy, so I'd reccomend burning that to a disc because you leagally won't be able to download another version.