On March 31st, 22 Microsoft exams from the Windows 2000 track retired. You can view the complete list [url=http://www.microsoft.com/learning/mcpexams/status/examsretired.mspx]here[/url]. Microsoft states that some of the exams may be available for a short grace period beyond this date. Check with Prometric for availability. Retirement of these exams does not invalidate any certifications that you may hold.