@Peru Bob,
Unless there is some very recent development I don't know about, CS4, CS5 and CS6 activation servers are still working. However CS1, CS2 and CS3 are gone.
@bwsword,
If you purchased CS4 as an upgrade, you will also need your qualifying product's serial number.
Please log-in to your account below.
https://account.adobe.com/products
Depending on your license, you may get what you need from the direct download links below. Be sure to follow the VERY IMPORTANT INSTRUCTIONS on that page or it won't work. And this won't work with Student/Teacher or volume licenses.
https://prodesigntools.com/download-adobe-cs4-and-cs3-free-trials-here.html
Failing that, Creative Suite is no longer available from any vendor, retailer or country now.
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 1 year subscription)
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!