First, just to be sure, you DID install Reader after you downloaded it correct?
If so, what happens when you open Reader, then use File>Open and navigate to the file and choose it?
I already said before
a window pops up with this on it
"This file does not have a program associated with it for performing this action. Please install a program or, if one is already installed, create an association for this program in the Default Programs control panel"
and I need help on what to do so that I can open the pdf file. Actually, when I open Adobe Reader (just by itself) the same message appears, and if I close the pop-up, adobe reader closes. If that helps
That is very unusual - it appears that the Reader is not installed correctly. Can you open Control Panel, then Add/Remove Programs, and uninstall Adobe Reader. Then reinstall it from http://ardownload.adobe.com/pub/adobe/reader/win/9.x/9.3.3/enu/AdbeRdr933_en_US.exe