Jo Marie,
You'll need your original Office installation media/disks to apply any
service packs.
If you had a legit copy of Office you can try here for a replacement: http://support.microsoft.com/default.aspx?scid=kb;en-us;326246
Likely that you'll be SOL unless you have Office XP or later...
If your copy was an original installation by the manufacturer (oem) you
should have a disk(s) to restore your machine to its original software.