IE recognizing ADE

[_Hector_Santore_]

Is there a known problem with Internet Explorer recognizing an installed instance of Adobe Digital Editions?

[_Piotr_Kula_]

All of the system requirements can be found on the following page:
http://www.adobe.com/products/digitaleditions/systemreqs/
All of the reported known issues can be found on this page:
http://www.adobe.com/products/digitaleditions/help/#known_issues

If those don't answer your questions, then could you provide some specifics about your system (i.e. what processor, OS, browser versions, etc.) and how the problem manifests?