From your description (went to a black screen and wouldn't work) it's not clear at all that reinstalling the OS would be the solution of this problem. To me, it's not even probable.

You can reinstall Windows from the full CD, if there's no Windows 98 present. Formatting the hard disk is a secure, but rather crude way of doing that, and you will lose everything that's on the hard disk.

The usual solution to this dilemma is to rename c:\windows\ to anything else (like c:\windows\win.old). That's the trick to tell the setup there isn't yet a Windows 98 on the machine. I assume you've got a valid productkey at hand to enter when the setup wants that.

The DOS-command, I think: rename c:\windows\ win.old

If that doesn't work, execute the following 3 commands:

A:\>c: to go to the c-drive
C:\>cd \windows to go to the windows folder
C:\windows>rename win.old

Then reboot from the diskette and try again.

Hope this helps.