I'd start with reseating the video connection the back of the computer. Do you have another computer or a friends computer to test the monitor? That would rule out an unfortunate coincidence.

Beyond that, I'd guess that the video card may be bad. If it's an actual card, rather than built into the motherboard, it's possible that it came loose in transportation and just needs to be reseated.

What kind of work did the computer shop do for you?

Also is it possible the tech installed a new video card and disabled the onboard video in the BIOS? In this case you should see a different video connection lower down the rear of the tower which you would need to connect to.

What kind of work did the computer shop do for you?
By accident, because of my lack of knowledge, I did a Destructive Recovery when I was stuck on a black screen with white lettering I couldn't get out of.
It brought me back to day one with problems that were fixed via Gateway phone support which is no longer.
One being not able to do windows updates and a shut down time problem. They were supposed to see if they could fix that and do all updates for windows and the drivers.
The computer (Win XPPRO) was brought in to find the cause of a sound that just started happening like a whirring speed up then down then steady starting after the computer is on for 7 minutes.
They said the heat sync fan/fans are OK and unplugged my floppy drive thinking it was that when the floppy had been known to make a short noise when I first used it when I bought the computer back in 2004 but hadn't since. A noise like it may have been trying to read? That was not the noise I meant.

Also is it possible the tech installed a new video card and disabled the onboard video in the BIOS? In this case you should see a different video connection lower down the rear of the tower which you would need to connect to.

Is that the socket I plug my monitor into as I noticed I could not push it in all the way to hide the silver part I thought did before? Then screw each side tight. Is that it?
If so, I bet they did but WHY?

Before I brought it in, everything worked fine except because of the Recovery two problems came back that had been corrected by Gateway I wanted fixed again and I was concerned about a noise that recently appeared, me thinking it was my HD or the sync fan.

Could be a pin on the monitor connector either pushed in or bent. Just a thought.

Terry

Are you sure that you're connecting the monitor to the correct port? The correct port looks like this:

As Terry mentioned check for any bent or missing pins on the cable coming from the monitor. There should be 15 and be nice and straight like those in the picture below (obviously you'll only have one connector)

{{gwi:1449039}}

I've also found that on occasion the screws can keep the connector from fully seating. You might want to pull back gently on the screw and/or unscrew it (turning counterclockwise). Ensure the cable is fully seated before engaging the screws.

Terry, no bent pins.
This what I have back there. (both)
{{gwi:1449041}}
Don't know why PB makes the pics so small?

Mike, Yes, That is the connections. The nuts on the computer that the plug screws into prevents my plug from pushing in any further than does leaving a little of the silver exposed.
I can't remember if it was that way when I bought it 7 years ago or even when I disconnected it to bring in for repair?
But I sure noticed it when trying to snug it up now. It is as if the nuts are too long.
I was wondering if all the updates of windows and drivers play a part in this problem? Hope he took drivers from the manufacturers.
I am bringing it back tomorrow and will update here my results with them. Thanks.

Just wanted to say, the darn thing booted up this morning?
I quickly went to check to see and my schemes has all three as never just like I had.

What happens is when I turn on my monitor, (1st) the green light turns to orange (power savings mode) before I get to push the power button on the CPU where it always stayed green before. Is that interfering with the ability of the CPU to turn on? (just a thought)
Next time I go up, I will turn the CPU on first, then the monitor to see what happens. One time when I pushed the power button on the CPU, it turned back off by itself.
Will experiment more so I have something to report to the shop.

I always boot up by turning on the tower first and then the monitor, otherwise the monitor will turn off since it isn't receiving power from the computer.

Same here... tower first then monitor.

Yes me too tower then monitor, if I don't then the monitor green on light comes on then goes to orange since it has no signal yet from the tower. Once the pc finishes booting though if I move the mouse the monitor comes up and all is normal. When yours had the black screen after green then orange light when you moved the mouse around did it not then come on?

It sounds like they may have set or changed the settings in your sleep and hibernate modes for the pc and monitor.

Come to think of it I usually turn the tower on first.(always as a matter of fact)
Don't know why I did the monitor first this time?
The noise was still there. Like a spinning noise.
I brought my computer back in this morning to check out the power supply and reconnect the floppy drive since that was not the problem.