How to Install Server Pack 1
You can download the ISA server service pack 1 from the following path
http://www.microsoft.com/isaserver/downloads/sp1.asp
1. Double click on the file isasp1.exe after copying the setup files on the ISA server machine.
2. Type in the path for the temporary files.
3. Click I agree on the EULA dialog box.
4. Click Ok to “Microsoft ISA Server 2000 Update Setup” and the computer will be restarted automatically.