do you know if its possible to interface my board with a computer keyboard so that if i pressed y it preformed a function and if i pressed n it preformed another, eg on and off.
Yes, it is. Now, I suppose you want to know how.
Well, there needs to be some application listening on the PC that reads the key presses, and sends them to the serial port.
Then, there needs to be some code on the Arduino that looks for serial data (Serial.available()) and reads it (Serial.read()) if there is any data to read.
Then, it's just a matter of calling the right function based on the data read.