I think you'll need to do a repair/reinstall of 98.
If you don't have a Windows installation CD, you may have a CAB directory on your drive, containing the installation files. The default location is C:\Windows\Options\Cabs,
but it could be C:\Win98, or something similar.
See this page for instructions, it applies to 98, as well. "Repair or reinstall Windows
without losing your software and files" click here