Compressed data

We currently have a dead hardrive which had Novell on it. The hardrive had been compressed and then un-compressed, so when we tried to use the back up data from the tapes some of the files were corrupted. Doing some research we discoverd that it wasdue to it being on a Novel compressed drive. So I wanted to know does anyone now how to fix compressed data. I.E. xls. doc. mdb.