Whereas the information provided by keith gladstien is correct vis-à-vis availability, compatibility, and security of Acrobat 7 as well as issues associated with using Skype with someone to get a solution, the fact is that if you indeed have a valid license for Acrobat Pro 7 and your operating system is Windows XP 32-bit or earlier, your license is still valid and Adobe can and in fact is legally obligated to get you an updated installer and serial number to install the software.
Unfortunately, the “chat” agents you were working with should never, repeat never, repeat yet again never have advised you to post in these forums for activation support. That support is not provided on what is essentially a community of Adobe end-users, albeit some expert end-users. Go back to support and immediately ask to be put into contact with a supervisor or manager until you get someone who knows how to get you the installer and serial number.
And again, don't correspond with anyone who claims to be from Adobe Support with anything other than a real adobe.com e-mail address who will Skype with you. They are total scamsters.
- Dov