New issue on the block after installing KB 973917. Checking event viewer you would end up with
Event Type: Warning Event Source: W3SVC Event Category: None Event ID: 1009 Date: 12/9/2009 Time: 10:55:01 AM User: N/A Computer: WEBSERVER01 Description: A process serving application pool 'DefaultAppPool' terminated unexpectedly. The process id was '9878'. The process exit code was '0xffffffff'.
To resolve this problem, reinstall Service Pack 2 for Windows Server 2003 on the web server.
Check out KB http://support.microsoft.com/?kbid=2009746
Before applying hotfix 973917 check whether it would break your IIS or not through this script
P.S: Script written by Punit Shah