
If you copied it to a different drive, change the drive letter.
In the “Variable value” field, enter c:\ffmpeg\bin after anything that's already written there. This is located in the first frame in the Environmental Variables window. Select the PATH entry in the "User variables" section. It will be located at the bottom of the window. Click the Environmental Variables button in the System Properties window. In the System window, click on the “Advanced system settings” link in the left frame. Select Properties from the right-click menu. Click the Start button and right-click on Computer. Copy the contents of the extracted folder into the new “ffmpeg” folder. At the base of the C: drive, where you see folders such as Windows and Program Files, right-click and select New Folder. Select the hard drive where Windows is installed (typically C:).
The folder will be named something like “ffmpeg-20130731-git-69fe25c-win32-static”. When you use 7-Zip to extract a file, it will create a new folder in the same location as the downloaded file. 7-Zip is a free archive program that you will need to open the FFmpeg file. Download the latest Static version in either 32-bit or 64-bit, depending on your operating system. When you visit the download page, you will see a variety of options.