Fdisk displaying incorrect disk size

[swm]

I recently upgraded my hard drive to a 40GB one and tried to install Windows 98 on it. It gets to the installation and says that the drive needs to be formatted (it already is), it goes through the format to 100% then spits up the following message:

Error
Setup cannot install Windows 98 on your computer.
An error was detected while formatting your primary hard disk partition.
Press ENTER to quit Setup.

I've reformatted, run ScanDisk and ran fdisk and it is still coming up with the same message, but a strange thing I noticed is that the partition says Usage 100% but is only 5810Mbytes big... The hard drive is 38,000-ish...

When I formatted the drive it said:

38,152.84MB total disk space
38,152.84MB available on disk

32,768 bytes in each allocation unit
1,220,890 allocation units available on disk

But in fdisk is says:

Partition C:1
Status A
Type PRI DOS
Volume Label
Mbytes 5910
System FAT32
Usage 100%

Total disk space is 5910 Mbytes (1 Mbyte = 1048576 bytes)

Which is wrong, but then for my slave drive:

Partition D:1
Status A
Type PRI DOS
Volume Label
Mbytes 6150
System FAT32
Usage 100%

Which is right...