In the task bar a balloon with "MTP device has been found" is coming. How to stop this?

Start --> Right Click
Select Properties --> Select Properties
Select Taskbar --> Click Customise box
Click "Show hardware devices" (Some times you may see 'No title'. Select that)
Select "hide when inactive" (on the right)
Change it to "always hide"

This will allow you to use 'Add New Hardware' in Control Panel.

"always hide." This will allow you to use add new hardware, you can then delete the devices

To know what is a MTP device? click here.

Click here to know what is MTP?

What is MTP?

MTP is the short form of Media Transfer Protocol.
This protocol is required to download audio files  from digital audio players and movie files from portable media players like mobile phones.

By Installing Windows Media Player 10 or above you can enable MTP in your PC.

All video files are playing very dark. How to play it normally?

If you are using Windows Media Player

• Select Preferences
• Disable Overlay

If you are using VLC Media Player

• Select Settings
• Select Preferences
• Select Video
• Disable Overlay Video output