|Unfortunately, as with most things, they were working fine until they stopped working. These things just happen...|
As you are already in Safe Mode you could try the registry restore given in response #1. It is quite easy if you take it step by step, the main thing being that you must type the commands "exactly as given" and then hit the Enter key. You should be able to restore a registry with a date that is before the computer failed.
If that doesn't help we could try some simple commands that might fix it.
All we can do from here is suggest ways to help YOU to fix it. With Win98 this almost always means typing in commands - sadly there is no quick mouse click or other that is likely to help with this particular issue.
Always pop back and let us know the outcome - thanks