Why Can't I Get The Motherboards Integrated VGA Video card to except My Monitor?

I just got a computer from a neighbor and brought it to my house the computer had been refurbished, It is a Gateway Computer ("Model: GT4016"). This computer was given to me and I'm having a hard time with it. When it was refurbished it came with a lcd Gateway monitor that works ("I tested it on another computer") so I put the Gateway GT4016 computer all together and The monitor has no signal. So I opened it up and checked it. The computer has no burn marks or smells and looks new and I took a look at every part and there's no problems or damage. So I put it back together after it was taken apart and still no signal. I took that computer brought it to my friends house. Using his monitor the computer worked. His monitor is a (lcd acer) thinking the problem was fixed came back to my house pluged it in to the monitor. There was no signal then I use one of those really bulky monitors same problem.

I'm thinking it maybe a Glich with the integrated vga video card in the motherboard but how can I stop it?
 
Hey Demkon_5. The only common element I see is that it doesn't work at your house. Does the monitor have a detachable video cable and if so, did you use this same cable at your friend's house and on the older tube monitor?.
 
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