have to reinstall dreamweaver 4 with 8 upgrade. serial numbers don't work

MODERN CODE EDITORS:
-- Adobe Dreamweaver CC - https://www.adobe.com/products/dreamweaver.html
-- Atom (free) - https://atom.io/
-- Codespaces (free, browser-based) - https://github.com/features/codespaces
-- Nova (Mac only, formerly called Coda) - https://nova.app/
-- Pinegrow - https://pinegrow.com/
-- Sublime Text - http://www.sublimetext.com/
-- Visual Studio Code (free) - https://code.visualstudio.com/
-- Wappler ~ Visual Web App Builder - https://wappler.io/

The activation servers for Macromedia DW8 (aka CS2.1) were de-commissioned many years ago.

It might be possible that your newer replacement computer does not support CS4 (which is what I am assuming since 8 --> 4 would be backwards).  For instance, if you are using a Mac, they are now 64-bit only and CS4 was not a 64-bit application.  If your newer computer can still run the software, you can try this KB article if you are on Mac: https://helpx.adobe.com/creative-suite/kb/troubleshoot-activation-problems-creative-suite.html . You can also try this KB article which includes items for Windows if you are using that OS: https://helpx.adobe.com/download-install/kb/activation-deactivation-help.html .