There are a number of ways
Code:
whereis openclipart
if it is an executable.
Code:
sudo updatedb
to update the database of files on the machine.
Code:
locate openclipart
to find all references.
Code:
locate openclipart | grep desktop
to find the(a) menu entry if it's there and too many 'openclipart' are displayed.
Code:
cat /usr/share/applications/openclipart.desktop
if that's the real name of the file. See what name it's listed under in the menu. It might be in a subcategory that has no entry and therefore invisible.
sudo medit whatever file to fix it. Use other files to give you an idea.
It depends if you have the name right. You may have to broaden the search until you get a return that allows you to be more specific to to solve the problem.