If you are talking about Acrobat Pro, Adobe turned off the activation servers around 2016. If you had before then registered your licensed activate copy on Adobe's website, it's possible to download a no-activation required installer plus working serial. Keep in mind it's probably phoning home everytime you use it, so if you want to use that installer and key on 2 computers, Adobe may decide to deactivate all installs with that serial and invalidate the serial (why I haven't tried that).
I found out about this at work while moving my copy of Acrobat Pro v8 to my new PC (Win7). V8 was the last one before the MDI was removed. Without MDI, Acrobat Pro is useless (for me). Fortunately I had registered the program around 2010 and was able to get the no-activation installer and serial. It works fine on the new machine.
At home, I suffer with the feature lacking free Acrobat 7 Pro. I would love to have v8 installed. I have a legal purchased retail copy and license of v8, but I never registered it on Adobe's site, which means I can't get a serial for the no-activate installer.... I spoke with their tech support and the basically said in many words "tough". There are no cracked copies of v8 that don't have a virus, so I'm out of luck.