Memory Leak u can find by using any performance tool like 
Load Runner, Silk, Performance Monitor etc..

To know ur self you can do one. 

1. See the free space in ur system.
2. Run ur Application.
3. See the free space again after completion of ur 
application.
4. If you have some difference between two free spaces find 
in previous steps gives you the memory leak. If you don't 
have difference means no memory leak.

This is one approximate method. But don't do anything while 
doing this process. 

Or you can use Performance Monitor(free tool with OS) by 
creating some counters.

By Endurance Testing we can find Memory leaks .