At least once or twice a week someone asks me about a couple of common features in Windows 98, most notably the blue Scandisk screen and the boot option screen. They are built in features to Windows that allow you to diagnose any possible problems.
People are probably most familiar with the blue scandisk screen.
Most often from a power outage, or crash. You have one of two choices. Let it run, or cancel it. If you know why your system was not shut down correctly, just skip it. If you aren't sure, let it run.