Hello, I've had my computer for about a year and 3 days ago it crashed for the first time while i was playing a dvd on it. I had to turn it off then back on again, but since that point the only thing that comes up on the monitor is NO SIGNAL INPUT and i know all the wires are fine and in place. I've read this could be something to do with the graphics card? Is it just a case of changing it? Is it pricey to do this? Any help would be brilliant thanks!

Certainly is symptomatic of a basic hardware failure. Could be the Graphics Card.

What is the make & model of the computer? If custom built what is the make & model of the motherboard? What about the make & model of the Graphics Card? Did you add it or was it pre-installed?

You might try clearing the CMOS. You might try on-board VGA (if available). Graphics cards run from @ $50 to $1,000 depending on what you want.

If we know the basic ID's we can research the options.

Do the fans run? Does the computer appear to be running? Hard drive etc.? Hear it? Feel it?