A very interesting question you raise about Windows 98. Although the Windows 98 exam is still listed on the MS Web site at http://www.microsoft.com/trainingandservices/exams/examasearch.asp?PageID=70-098. You can't get there from any of the current, valid, multi-exam certification programs that Microsoft currently recognizes (such as MCSE, MCSD, etc.). The way they word the MCP requirement is as follows "Microsoft? Certified Professional (MCP) candidates are required to pass one current Microsoft certification exam that provides a valid and reliable measure of technical proficiency and expertise (a current exam is any that has not been retired)." I think you can still get an MCP by passing 70-098 but it won't lead you to anything further and it's bound to be retired next year, if not later this year.
This was first published in April 2001