Help! I can't get my Photoshop CS6 to work.

Adobe has removed ALL public download links for serial number programs
-links are ONLY available to someone who purchased a download from Adobe
.
For serial number programs you may download ONLY if you bought direct from Adobe via download
-Log-in to your account and click this link https://account.adobe.com/products
--click Order history on the left and then the link to your order that will show on the right
--and finally click the link "Downloads and serial numbers" that will appear
---as always, write the serial number in a text file AND copy that text file and the
---download file(s) to an external drive (or two) to be sure you have what you need
-if you did not buy direct from Adobe via download you must find your original install
-if you have an Education or volume license you MUST use your original media
--the link for an Education or volume license download is not available at all
-if you bought a disc and don't have a drive you will need to buy an external USB drive
-if you bought and lost a disc Adobe does not provide a replacement via download
-if you bought a download from a 3rd party vendor you will need to contact that vendor
.
When you do have a download, be sure to copy it to at least one external device
-a usb flash drive or hard drive, or write to a DVD
-plus a text file containing your serial number

Wow. Thats a huge bummer! Especially since I can't find my original download or serial number. I downloaded it a long time ago, and I don't currently have the disc. Any suggestions for that?

The reason is that As soon as you install any part of the Cloud, even a trial, it replaces your program management system
-if you plan to keep using CS6 (or earlier) you should NOT install a Cloud program, not even a trial
-Read Cloud takes over https://community.adobe.com/t5/Get-Started/Get-off-the-cloud/td-p/8075485 for some ideas

You will need to uninstall both CC and CS6 and reinstall CS6.

Use the Cleaner Tool:

https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html