KOBO E-reader icon does NOT appear when kobo connected Adobe Digital Editions 2.0 is opened

2 months ago I was able to use Adobe Digital Editions 2.0 to borrow E-books from public library,   I have tried multiple times this week, , following exact procedure which was successful in past. and the KOBO icon fails to show up in lefthand column  My librarian says lots of people have problems with Adobe . Do I have to go through the hassle of uninstalling , then Re-installing Adobe ?  Am NOT computer literate.