password forgotten to inactive email address

Hi,

i updated the ADE 3.0 to 4.5 but it's incompatible with Kobo. I try to download books from the library (Overdrive) to ADE and a few will transfer but many don't, so I can't read it on ADE nor on my Kobo. So, I have to uninstall it and install the ADE 3.0 however, it's authorized with an old email address that is no longer active and I have forgotten the password. How do I go about this. Having read my situation which would be the best steps to follow?

Thanks