The Evernote "not responding" was a total nightmare for me to resolve. Was very close to abandoning Evernote altogether after years of paid service. I uninstalled and reloaded the program, tried just using the web based portal, moved to a different computer, reformatted my computer and reloaded all my software, ran through the defrag/ consolidation protocol deal for Evernote, and it would still hang up on me all the time "Evernote "Not Responding"". Had trouble doing my job at time because I had become so dependent on this tool.
Cut to the chase. I had a couple of corrupted notes. Two notes that I use frequently had somehow made Evernote unstable. I copied out the useful information from those notes and created new ones to replace them. Since this has been done Evernote has not been hanging up on me. I have been able to go back to using the tool as usual, but I must say that this whole ordeal has made me really reconsider how much I rely on this tool day to day. Hopefully my experience will help someone to resolve this issue quickly or will highlight a glitch which the Evernote folks will work to resolve.