When I put my computer on it comes up with scanning no signal and the screen stays black with the little light in the corner is yellow but sometimes leaving the computer on by itself

try to remove memory the put it back

It is the fault of your data cable please change it, your problem will be fix.

good luck

When it lights up the yellow light instead of the green one, that means that the monitor is not getting a signal from the computer.
The things to try (from simplest to most complex) are:

1. Make sure the computer is on and not in "sleep" mode -- press the "Caps Lock" key and see if it lights up the caps-lock light on the keyboard.
2. Make sure the video cable is connected from the computer to the monitor (that the cable hasn't come loose on either end)
3. If your monitor has multiple inputs, make sure it's set to the right (probably analog VGA or DVI) input
4. If your computer has more than one video output (like a laptop with it's internal screen plus the external monitor) then make sure the external monitor is enabled

If none of those solve it, post a comment back here and we can dive in to the more complex tests

Try another monitor on your computer. If you still get a blank screen then its an issue with the computer not having any video coming out of the video card. If you hook up another monitor and you get video then its an issue with the original monitor.

Also try the original monitor on another computer and see if video comes up. If you still don't get video, that would mean the monitor is bad for sure since you would have tried it on two different computers.

Replace your monitor power cord

The fault is a back-light problem and the fault could be a faulty inverter board or a faulty CCFL lamp.
For service, parts and DIY info check out LCD Parts WEB site, please click on this link :-
www.lcdparts.net

turn off the computer and get a can of compressed air blow out all the dust and make sure everything is tight put back together and see iff it works. geek squad charges 99.99 to do this in store.

I found some solutions other posted that didn't come up the first time I looked. I did a reboot and I'm good to go!

You have to use the FN key and F5 to change between the LCD screen and the external monitor. It may be F8 also, depending on the laptop model.

Look on the F keys for a little picture of a monitor.

Once you have found it, hold the FN key and tap the F key and it should switch to the external monitor.

check the cable which connects from the monitor to cpu is connected properly... if it s not connected properly this problem occurs.. just reconnect it ... ur problem will be solved...