A few months ago our computer screen started showing a whole bunch of random colors and letters everywhere. my wife had a friend look at it and he said it was the graphics card. we couldn't afford one right away but we got one a week ago and I put it in my computer and every time i try to start the computer up the screen just stays black after it shows the dell logo. The card we got is GeForce GT240 1GB 128bit DDR3. I need help with it asap.