Hi my name is Bob and I am having problems downloading library books to my sony prs t2 reader

When I download to the reader it has no cover and then when i try to open a book it tells me its DRM protected .Both my lap top and my e-reader are authorized for each other. I've tried everything possible but I just can't get it to work . First of all when I plug in my e-reader it won't show up on the Adobe Digital Edition. Why is that? Any help would be greatly appreciated. Bob