prathapml, you sure have a lot of posts. Is the information on the Office 2003 without product key post of April 15, 2005? This looks like it might be it: CODE setup.exe /QB PIDKEY=YOURSERIALHERE office2k3-sp1.exe /Q regedit /S clear-key.reg the first line installs office silently with the specified key, and second line installs SP1, and third line clears key. The clear-key.reg has to be made from notepad, copy/paste the below into it: CODE Windows Registry Editor Version 5.00 [-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\11.0\Registration]