T.v.just has no signal on the screen

first off i have no remote control.my tv just displays no signal when powered up.the power button,source button,menu button etc. are not responding. the tv was ran with the computer. i believe the cable and every thing was ran threw the computer.i tried reconnection of the computer nothing happened.i tried connecting the dvd player still nothing happened. why does the tv just say no signal and doesn't respond to the buttons. is there a way to reset the television without a remote control