A technology blogger from India, called Nirmal showcases on his website a free tool that you can use to enable thumbnails for all video formats in Windows Explorer. I found this surprisingly useful and I would like to share with you Nirmal’s tutorial and the tool being used for the job.
The tool in question is called Windows Media Preview and it offers downloadable clients for both 32-bit and 64-bit editions of Windows 7.
You can find a tutorial on how to use it here: Enable Thumbnails of All Video Formats in Windows Explorer.
The tool can be downloaded from here: Windows Media Preview Download.