Windows 7 Cannot Install any downloaded program

I recently have noticed that I cannot install any downloaded programs. For example, I've tried to install Avast Antivirus and Spotify programs I downloaded from the internet.

I can run other .exe programs that were previously installed like Chrome, Itunes, etc. but keep getting errors with the above .exe programs.

I have Windows 7, 64b, SP1

It's quite a common problem with Windows 7. This version of Windows is incredibly paranoid about the Program Folder. You can try to

1. right click on the installation exe, and choose "Run as an administrator"
2. use "Take Ownership" Add "Take Ownership" to Explorer Right-Click Menu in Win 7 or Vista - How-To Geek
3. install directly to C:\ or something --- avoid Program Folder