application
 

when i install applications like instant messaning or kazaa, where can i find it? the kde start menu?

yes, if they're set up to make shotcuts there....if not, then just find them :) usually they reside in /usr/bin or /bin or in other bin-directory, so that you can run them just by writing the executable's name in terminal (no path needed). or just write the beginning (like "kaz" without quotes) and press TAB so the rest of the name is displayed or then the names that equal the beginning.

if you wish to see where they are, do either

whereis command

or

locate command

where "command" is the name of the executable. for the locate-command you need to do "updatedb" after installation if it's not done, so that it finds the file. whereis finds it if it's in some bin-directory.