Is this the only drive in the system? If so, did you partition and format the hard drive yet? If not, make sure your bios is set to boot to floppy first and boot to a Win98 startup disk. Then partition and format the drive. If it has been partitioned and formatted, boot to a Win98 startup disk and type the following:
FDISK /MBR
Then type:
SYS C:
Hopefully this will take care of your problem.