I've branched this to a new discussion for you as the other one is unrelated to CS3.
CS1, CS2 and CS3 are dead & gone. The activation servers were removed from service years ago. Even if you have an installer with a compatible valid serial number, it's impossible to activate the software.
MODERN OPTIONS:
Photoshop or Premier Elements 2020 (approx $100, no subscription needed)
https://www.adobe.com/products/photoshop-elements.html
Creative Cloud Photography Plan -- approx $10/month for 12 months. Includes the very latest versions of these great products & services:
-- Photoshop and Photoshop on iPad
-- Lightroom on desktop, mobile and the web
-- Lightroom Classic
-- Portfolio website + hosting
-- Spark with premium features
-- Bridge
-- 20 GB cloud storage (upgradable to 1 TB).
https://www.adobe.com/creativecloud/photography.html
Creative Cloud All Apps Plan (31 + apps & services)
https://www.adobe.com/creativecloud/plans.html
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Beware of fake Adobe reps who may contact you privately offering to sell you software or take control of your computer. It's a scam, run away!
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3 Easy Ways to Identify Genuine Adobe Staff
https://tinyurl.com/10791730