I want to allow only one instance of the application to run on a particular system. If the application is already running and if the user tries to invoke the other instance it should not. 

Hi,

http://blogs.msdn.com/onoj/archive/2004/06/04/148532.aspx

OR

I Don't really rember there is Some setting In project Propety which Allow single Instance..

All of these are using the Win32 API's. Is there any way to do it without the API's 

This should help

http://www.ai.uga.edu/mc/SingleInstance.html

U may Also Use GetProcess()

Use GetProcess() on Load Chk is process is there if There then Donot Allow the user to Load else allow

http://www.java2s.com/Code/CSharp/Development-Class/GetProcessproperty.htm

http://www.howtogeek.com/howto/programming/get-a-list-of-running-processes-in-c/

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