[RESOLVED] No VGA input signal, monitor going to sleep

I am trying to fix my sisters computer but am getting no where. At her house when she turns on her monitor it says
VGA input
No input signal
Recommended settings 1280x1024-60Hz
then it says monitor going to sleep.
She has one of those flat screen monitors and a Hp Pavillion a 1712n running Windows Vista Home Premium

So I bought it over to my house and hooked it up to my Dell monitor and all I get is a blank screen.
I have a Dell monitor and computer running windows xp home but I am only using my monitor with her computer.
Can anyone help me please?

I went back to her house and got her keyboard and monitor and her monitor works with my pc but my monitor won't work with her pc.By the way I can't even get into safe mode or get her pc out of sleep mode. help please

It sounds like the problem PC is not even powering up. What is the make and model? What activity (if any) takes place when you press the power button - Ligts, fans, drive noises, etc.?

OK, the problem is not with the monitor, but her PC. When you turn it on does anything happen at all, such as fans spinning, lights coming on, etc.?

her pc powers up and everything,i even hear the fan running, just no picture. Her pc is a hp pavillion a1712n running windows vista home premium and her monitor is a hp vs19e

Try clearing the CMOS in case it got scrambled. There should be a jumper on the motherboard to do that, if there isn't or you can't find it then pulling the motherboard battery out for a few minutes will achieve the same result (unplug the power lead as well).

is there another way because this is my sisters computer and it is only almosy a year old and i would hate to mess something up by opening the case

If you can't get anything to display on the screen, there probably isn't another way. If it is under warranty, warranty service might be an option.

I reseated the RAM and the battery and it worked once so I went in and changed the display settings and restarted to make sure it worked and now I am back at square one

Update: I was able to get it to boot a couple of times and go in and change the settings but after it would not restart and I shut the power off and turned it back on everything when back the way it was.

It sounds like a dead motherboard battery then. Get a CR2032 battery, and see how it is then.

HP seems to think that the motherboard is shot. I was able to get the computer online to day.What do you think?

I think you should do what SuperSparks suggested..

If it is booting up intermittently, then the motherboard MAY be OK. It could easily be the power supply that is causing the problem. Other possibilities incoude bad memory, or bad capacitors on the motherboard. However, if it is still under warranty, and you can get HP to replace the motherboard or fix whatever problem it has, that may be the way to go.

as luck would have it, it is not under warranty anymore.I am about to go buy a brand new battery and see how it does.Hopefully that is all that is wrong with it.BTW, the mother board is A8M2N-LA manufacture is ASUS

ok, just put in a new battery and nothing has changed.I am still getting the monitor status box