Windows 98 Second Edition Shutdown Supplement
Microsoft has released the Windows 98 Second Edition Shutdown Supplement that addresses shutdown issues on computers with specific hardware and software configurations running Windows 98 Second Edition. These issues include computers restarting when shutting down and computers hanging on shutdown.
Microsoft recommends following the troubleshooting steps that are outlined in this article. If, after following the steps that are outlined in this article, the computer continues to exhibit shutdown problems, Microsoft suggests applying this update.
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q239887