Adobe Creative Suite 6 Master Collection

Who did you purchase from?  If it was not purchased directly from Adobe, contact the vendor who sold it to you (if they're still in business).

Failing that, you'll need to get replacement software that's compatible with new computers.

MODERN OPTIONS:
Photoshop Elements or Premiere Elements (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 following:

• Photoshop CC and Photoshop on iPad
• Camera Raw
• Lightroom on desktop, mobile and the web
• Lightroom Classic
• Portfolio website + hosting
• Adobe Express (free starter plan)
• Bridge
• 20 GB cloud storage (upgradable to 1 TB).
• Free upgrades for paid subscribers

https://www.adobe.com/creativecloud/photography.html

Premium Adobe Express ($10/month).

• Adobe Express app (web and mobile)
• Premiere Rush (video editing fro desktop and mobile)
• Photoshop Express (mobile)
• Spark Video (mobile)
• Spark Page (mobile)
• Adobe Portfolio + hosting
• 100 GB of cloud storage
• All premium templates and design assets including the collection of over 160 million royalty-free Adobe Stock photo collection.

https://helpx.adobe.com/express/using/express-overview.html

Creative Cloud All Apps (51 + apps & services) and Single App Plans
https://www.adobe.com/creativecloud/plans.html

Hope that helps.

See here:

https://helpx.adobe.com/x-productkb/global/invalid-revoked-serial-numbers.html

and here:

https://www.adobe.com/genuine/landing-dnr.html?promoid=791Y6S4Z

if the serial number is revoked, you have only one option (after double checking you entered the 24 digit number you intended): contact adobe support.  they won't usually offer any support to help you install, but they often will tell you why the number was revoked, or if it's not really revoked.

if adobe support un-revokes that serial number and you need more help installing, return here.  actually, please post the follow-up of your contact with support no matter how it goes.

there are 3 ways to contact adobe; chat, phone and twitter:

chat:
use a browser that allows popups and cookies, and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

phone:
https://helpx.adobe.com/contact/phone.html

twitter:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true