Your PC's default reader configuration for embedded PDFs has become confused, due to multiple Adobe PDF document solutions installed on one PC.
Go to Start > Run
Type regedit and click OK.
Browse to the following key: HKEY_CLASSES_ROOT\Software\Adobe\Acrobat\Exe
Make sure that the correct Default data value is set for the path where Adobe Reader or Acrobat are installed.
The default installation values are:
"C:\Program Files\Adobe\Reader 9.0\Reader\AcroRd32.exe"
"C:\Program Files\adobe\acrobat 6.0\acrobat\Acrobat.exe" (not sure about this path. Check on your PC to be sure)
depending on whether Adobe Reader or Adobe Acrobat is installed.
Configure the browser to use Acrobat or Adobe Reader as a helper application.
If you are using Firefox to browse the web, you can change this setting in Firefox by going to:
Tools > Options
Click on the "Applications" Tab.
The first item in the list should be "Adobe Acrobat Document". Under the Action list, click the drop down arrow and select the application you want to read PDFs within the web browser. Click OK, and you should be done.
If you're using Internet Explorer to view PDFs, try the below steps.
After you configure Acrobat or Adobe Reader as a helper application, the browser starts the helper application in a separate window and displays PDF files within that window. Acrobat and Adobe Reader both include a preference that lets you specify Acrobat or Adobe Reader as the helper application.
To configure Acrobat or Adobe Reader as a helper application:
Start Acrobat or Adobe Reader.
Choose Edit > Preferences.
Select Internet on the left.
Deselect Display PDF In Browser Using [Acrobat application], and then click OK.
Quit Acrobat or Adobe Reader.
The next time you select a link to a PDF file in the browser, a dialog box asks what you would like to do with the file. If you select Open It, the browser opens the PDF file in Acrobat or Adobe Reader (the helper application); if you select Save It To Disk, the browser saves the PDF file to your hard drive.
Thank you very much! The first solution worked. The user is very happy.