Hi,
Thank you for the update on the issue.
If you are unable to install Reader app then try to boot the computer in clean boot and disable security software temporarily. After performing this try to install the reader app as there could be chance that some security software or some startup items is restricting it to get installed.
Step 1: Perform Clean boot.
Putting your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue. You need to follow the steps from the article mentioned below to perform a Clean Boot.
How to perform a clean boot in Windows
http://support.microsoft.com/kb/929135/en-us
**Note:**Refer "How to reset the computer to start normally after clean boot troubleshooting" to reset the computer to start as normal after troubleshooting.
Step 2: Disable Security software temporarily.
Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
Hope this would help. If issue still persists post back with current status of your computer and result of the proposed suggestion, we will be happy to assist you.
Regards,