OK, here goes.
1) Add yourself to sudoers by becoming root -
Then entering your root password.
Then type -
Then add the line showed below in bold -
Code:
root ALL=(ALL) ALL
<username> ALL=(ALL) ALL
You will need to know a tiny bit about how to use the vi text editor to do that bit. Google it, it's not hard to learn the little bit you need.
2) Change back to your normal user by entering -
Then list the .desktop files by using the following commands
Code:
cd /usr/share/applications
then
This should list all the .desktop files in /usr/share/applications.
Then refer back to my original post on what to do with the .desktop files.
Finally, I will quote you -
"I used GUI filemanager, as I don't know how to get the listing of a directory's content's in Terminal."
A single google search would have found this information for you. I'm willing to help, as are loads of other people, but no-one is going to be willing to spoon-feed you for long.
Regards
spoov