Possible Duplicate:
I can't install software from the software center
After I press install it says:
Please check your internet connection
After I click ok, it says:
Require installation of untrusted packages , The action would required the installation of packages from not authenticated source
Can you help me? I want to make my flashdisk write protected. So no one can format my flashdisk because the data inside the flashdisk is important.
How do I set the default program that I use?
I have tried to open System Info → Default Program → change my program, but it won't work,
Any idea? Or should I use Terminal?
I want to replace the default movie player with VLC media player, because the current movie player is useless to me.