Windows 98 problem

Try to format your HDD using another HDD. Boot from another HDD, and format your previous HDD.
Please tell me if this works.

After formatting your hard drive did you re-install Windows 98se?? It might help to try to do that since when you format the hard drive it deletes your operating system!
hope this helps, Good Luck!

It sounds to me like your hard drive has crashed. You really don't give enough information to tell for sure. Another possibility is that maybe you have contracted a virus that has corrupted the boot sector of your hard drive.
Find the brand and model of your hard drive, then using another computer, go to that manufacturer's web site and look for a drive testing utility. Every company has one available. You will ba able to download the utility to one floppy. Boot your system to the floppy and follow the directions. Depending on the size of your hard drive it can take from 5 minutes to an hour to run the tests. If the drive comes up as bad check the company's website for warranty information and the date on the drive. Many HDs are covered under 3 year or more warranties.
The utility will allow you to write the drive to 0 s and do a wipe of the system. If you HD is good try wiping the system and reinstalling your OS.