Adobe Indesign CS3 -- Activation problem

I'm having a problem re-activating my copy of Adobe Indesign CS3 following a move to another PC; getting the "no connection" message.

I had an on-line chat with support who directed me to a link whereby I could get a new serial no. and a new download of InDesign CS3.

I was told to uninstall my current copy, then reinstall using my new download and new serial no., after which I could activate.

I did all this but when it came to installing, there was no option to use my new serial no. Instead, on launching, it went straight to the activation screen telling me I now have four days left to activate!

The telephone option doesn't work any more but I checked there and noted my old serial no. is still there which seems to indicate it is permanently stored somewhere in the registry?

Any advice on how I can get round this problem, please?

Yes you are right, I am on my own given that my purchased InDesign no longer works.  On the upside it has prompted me to look for other packages less expensive than InDesign.  With minimal research I have found Microsoft Publisher, which I already have courtesy of Microsoft Office plus the free Scribus and a host of other packages, most cheaper than InDesign.  I feel re-invigorated.  

Windows 10 and I have just seen the comment by Bob Levine saying CS3 is not supported by Windows 10.

I have a problem installing a In Design CS3 replacement after downloading it. I have been given a new serial number but the installation by-passes the insert code screen.  I followed the suggestion of removing the cache.db file on the attached Adobe Support Community forum but can't find such a file, in fact there is no db files at all.  I have looked in every folder.  What do I do next?

I have indesign CS3 Ver. 5.0. It worked fine until the last update of Win 10. Now It asked me to activate.  If I install an older backup of Win 10 it works again. Can You please tell me which cache.db I have to delete for installing the new got Ser. Nr.