if it was working before and you have not tinkered in the case, then the only conclusion i can come to is that it is fried.
I'm sorry. I don't mean to be rude, but that's really bad advice. There could be a LOT more going on here!
detroitpistons05: The first thing to find out is if there's any data on your second disk. If so, it may be formatted in a way that Windows 98 can't read. For example, if the disk came from a newer Windows version than 98, it's likely formatted as NTFS, which Win98 can't handle. In that case, re-formatting the disk as FAT32 should do the trick.
Also, reboot the machine and check to see if both disks are recognized in the BIOS. You do this by pressing a specific key right after the computer comes to life (often ESC, F2, or F12).
If the disk is FAT32 and it's recognized by the BIOS, then we can try some other things. Check those and report back!