Recovering CS5 serial number or download files

IF/When you do have a download, be sure to copy it to AT LEAST one external device
-you should ALWAYS keep a copy (or two!) on an external device
-since Adobe DOES SOMETIMES REMOVE OLD VERSIONS FROM THE SERVER
-a usb flash drive or external hard drive, or write to a CD or DVD
-plus a text file containing your serial number if you have a serial number program

you can download from here http://prodesigntools.com/all-adobe-cs5-direct-download-links.html 

you'll waste your time if you contact adobe support about this issue.

The following article might help

https://helpx.adobe.com/in/creative-suite/kb/install-creative-suite-5.html

I don't think Adobe support provides any support for CS applications apart from resetting the activation count. However, if nothing helps you may try contacting them as well.

To contact support follow the instructions given below
1. Go to https://helpx.adobe.com/contact.html?rghtup=autoOpen
2. Wait a bit on the page that opens up, it should automatically open a chat popup. If that does not happen then look for a call out/chat icon at the bottom right, click over it and the chat popup should open
3. In order to talk to a human type "AGENT" in the chat box
4. If you are not able to get to the chat window, then disable your adblockers, firewall, enable cookies/scripts on your browser. If it still fails then change your browser/machine/network.

P.S. Be mindful of answering anyone who sends you a private message. See the following for more information about scammers
https://tinyurl.com/y7cfrr7y
-Manan