1. Insert the Office System (2003) CD into your drive, from the "Start" button select "Run" and type
This is going to start the install process of Office 2003. You'll be presented with the option of where you want the files to go (I chose "C:\Office2003"), and you'll be asked to enter your CD key.
After entering the CD key, you'll be presented with the End User License Agreement. Accept it then continue.
It's going to appear to be installing, but in fact your files are being copied over to your hard drive.
The completion window will pop up and the entire Office 2003 CD is now copied to your hard drive.
2. Extract the Service Pack files
office2003SP3-KB923618-FullFile-ENU.exe /t:c:\Office2003SP3 /c
All the office2003Sp3 files are copied to c:\office2003sp3 folder
Start the "Run" command from your "Start" menu again. Enter the following command:
msiexec /p c:\Office2003SP3\MAINSP3.msp /a c:\Office2003\PRO11.MSI shortfilenames=true /qb
office sp3 is updated to folder c:\office2003.