You've pretty much identified that it's not running - stop using the system before it suffers damage, and have it repaired.
Hiya, could you tell me where the dell diagnostics thing is please as i am pretty sure my fan has stopped on by Inspiron 1520 as it used to be very noisy and i cant hear it at all and cant feel it blowing either. are they expensive to repair?
Press F12 at powerup to get to the diagnostics. DO NOT use the system if the fan isn't working. A fan is cheap - a mainboard or video card that fails due to overheating, is not.