Why do you need InDesign CS (that is version 3) or InDesign CS3 (that is Version 5) to install InDesign CS5.5 (it is version 7.5)?
If it is an upgrade and asks you to input your serial of an older version, you have to get an find it. No one will help you here. If you can't find it and if you have not registered it, you are out of luck. You will have to spend money for a new version.
I was afraid of that.... Thanks!
If you still have the installer disk for the previous version, you should also be able to use that to verify the qualifying program for the upgrade, even without the s/n, but if you had the disk you would probably also have the s/n sticker on the back of the case, so....