Under the help menu is an item for repairing your installation of Reader. Have you tried that?
I tried that, and it still won't open up Adobe files on websites.
I have this same issue across our network in the office. We actually run 3 PDF managers simultaneously for various reasons, but the issue you are having is the same as what we are encountering. Most workstations are on XPPROSP3 and IE7 Silverlight. I did come across a procedure in another
Forum that has supposedly repaired this issue:
Close all IE Windows
Open Adober Reader or Acrobat
Select EDIT from menu
Deselect PDF in Browser
Return to EDIT menu again>Preferences>Internet Category>Select PDF in Browser
Press OK and close application
Relaunch IE and try to open a PDF
The other suggested repair is to run the repair install from within Adobe. I have tried the above and ran the repair from Adobe as well as Control Panel Add/Remove Programs, Reinstall/Repair. It is slightly more complicated in our environment b/c of the other PDF viewers/managers we use for various reasons. Still researching and testing for issue resolution. Try it.
Thanks, It works now.