i have two simple c# form programs, and I want to make a button in the first program start the other form when i click it, but i dont know how to access the other programm.cs ma
You have to use the Process class of the System.Diagnostics namespace to start the second program, refer to this article on the MSDN,
http://msdn.microsoft.com/en-us/library/system.diagnostics.process(VS.71).aspx