Need to download adobe digital editions version 3.0 and I can't seem to

I have a nook simple touch w/glow light.  when I download the new adobe digital editions 4.5, it doesn't work.  So I am searching for a download of adobe digital editions 3.0 and I can't seem to find the right thing on the computer.  Sometimes it sends me to Acrobat Reader - is this the same thing?  Will it work for ebooks?  Or I find a site to download and they are selling it or trying to put other things into my computer.  Been trying to deal with this problem for 3 days now (1st problem was I had no idea version 4.5 and the nook touch weren't compatible) - why is the download for the 4.5 so easy yet the 3.0 so difficult to find? thanks Debra