BAD FAT ON MY HD

I have 2 hard drives of 12 gigs on my laptop.
A few weeks ago, My computer crashed. The hard disk would not boot. It seemed to be the fat. In command prompt only, I copied important data from the c:drive to the d:.

I then reformatted the c: drive and reinstalled Windows 98. Now windows 98 refuses to read my d: drive saying that it is not formatted or locked by a disk utility. It suggests i reformat the drive.

How do I recuperate my data before reformatting or losing it?