You won't be able to do a repair install with 98 - you're stuck with formatting and a clean install, assuming your hard drive hasn't bit the dust.
If you have a startup disk or can boot to a command line, you might be able to get the ME going again. Start by tapping F8 while the computer starts, right after the memory check, and choose to start with a command line and type
. . . and choose a registry that started.
If that doesn't work, you may try a ME startup disk and either fix the master boot record or replace the system files.
Read through this
and see if it helps.