Normally Acrobat Reader take time to open. Here is the trick for which your Acrobat Reader opens like NotePad.
1. Go to the installation folder of acrobat reader
(C:\program files\adobe\acrobat\reader\.. whatever)
2. Move all the files and folders from the "plugins" directory to the "Optional" directory. (I repeat.. cut and paste the files NOT copy & paste).
Note:- Also make sure that acrobat reader is not open else it will lock the files and not allow you to move the files).Now your acrobat reader will load very fast and almost as good as notepad