Invalid Serial Number when I tried to reinstall

I have an old old version of Photoshop Elements, it's version 7.  I recently had to reinstall windows so I downloaded the installer from my Adobe account and installed it.  But when I tried entering the serial number (copied directly from my adobe account), it says the number was invalid.  I've installed this version this way several times before without any issues, so I don't know what is different this time.  I  tried to connect to an agent through chat for an hour and nothing.  So what is going on here?  Before anybody mentions, it is a completly valid version, not purchased on ebay or amazon.  It came with my Wacom tablet.