i can not get adobe digital editions 2.0 to open on my pc.now i cant drop new books on ebook

Are these DRM books, or DRM-free.  If DRM-free, use the free and far superior Calibre ( http://calibre-ebook.com/)

There are lots of bugs in ADE2.0 (and 2.0.1).  Try replacing ADE2.0 with the older but more reliable v1.7.2.

(You can have them both installed at once if you like.)

Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.

http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editions.html

The forum software is sometimes corrupting the link above.  There shouldn't be a blank in 'editio ns.html'.  The following redirects to the same page: http://tinyurl.com/diged172