Disk compression error

Here’s a tough one. One of my clients with disk compression installed on his Win95 machine tried to uncompress his C: drive, but stopped half way, leaving him with half of his data compressed, and half uncompressed. Is there any way to either recompress the drive, or uncompress it the entire way so that the data in the compressed drive can be retrieved? I’ve temporarily set him up with a new windows installation in another partition, but told him not to touch the partly-compressed/uncompressed drive. Any answers would be greatly appreciated!!!