Microsoft Internet Explorer often opens background processes (software that runs "invisibly" in addition to the main application) to perform various functions. But sometimes Internet Explorer doesn't properly end these background processes, even when Internet Explorer itself quits.
In this case, it looks like Internet Explorer has quit, but one or more background processes can still be running, which prevents the SlingPlayer plug-in from installing properly.
The workaround for this problem with Microsoft Internet Explorer is to manually end any Internet Explorer background processes that are still running.
You can do this through the Task Manager on your computer:
Close all Internet Explorer windows (if you can).
Open Windows Task Manager by pressing CTRL + ALT + DELETE and starting the Task Manager.
Click the Processes tab, and you see a window similar to this:
Locate the Internet Explorer task called iexplore.exe. (There may be more than one.) You may alternatively see a process entitled ielowutility.exe, or other similar Internet Explorer processes.
Click to select it, then click End Process. Repeat for any other instances of iexplore.exe.
Note: DO NOT do this for the process explorer.exe.
Continue installation of the Watch on Slingbox.com or Setup on Slingbox.com plug-in.
Note: This issue can occur with the Windows XP, Windows Vista, Windows 7, and Windows 8 operating systems.