This taken from bink.nu.
Please install MS03-026 patch NOW!
Reminder over a week ago MS released a critical patch for a security issue in RPC, All NT based Windows editions are affected Windows NT4, Windows 2000, Windows XP and Windows Server 2003.
If a worm is developed to use this exploit CodeRED and Slammer will look like child play. Please apply the patch ASAP, don't wait till after the weekend, codes to develop a worm are already posted in hacker forums.
NOW -> Microsoft TechNet security/bulletin/MS03-026.asp