NDS emulator problems. how to start pokemon diamond !

i dont know what emulator to use to play pokemon diamond,, i have tried other NDS emulators but when i open it it says the game crashed.. so what should i do ??? what NDS emulator do you prfer ??? i have the NO$cash emulator. . after i downloaded the game , shouldnt it say NDS file ?? mine says RAR file ?? help me out !!

Look in the general section for the solution. There's a whole topic on how to run the game. Also, you can extract the RAR file with winrar (it's like a zip, only different compression).