I have hooked everything up and the monitor shows " no signal".

the most common problem with LCDs today is failing electrolytic capacitors, especially in the power supply section. Look for bulging, leaking, blown or missing capacitors and replace them.

It could be a couple of things. If this monitor is hooked up to a computer, it could be a bad video card. A video card is easily fixed on a desktop, if you're using a laptop you're probably out of luck.

If it's hooked up to a DVD player, check that the cord to the monitor is hooked up properly (make sure the connection goes from the "Video Out" on the player to the "Video In" on the monitor and that all connections are tight, not barely hanging on). If that doesn't work, try a new cable.
This is probably insulting, but also make sure that the monitor is set to the right channel if it's multichannel. For example, if your DVD player is hooked up to HDMI 2, make sure the monitor is set to use HDMI 2 for signal.

If none of these work, it's time to find a tech-happy friend that can inspect everything visually. Hope that helps!

I'm not 100% sure about this as it sounds like a intermittant problem but I think your problem is going to be either the connector on either end or the cables.

All it takes is one pin not seated properlly or dirty etc and the signal could be out giving you the error. As long as it was only certain pins with a strong enough signal that would create your messages.

Basically all you need to do is take the cables off on both ends and then reseat them a few times. That will usually be enough to clean any corrosion and even straighten the pins.Alos look when you have both ends off for pins that are not long enough or bent out of shape. Don;t forget to check the connectors on the tv and cable box etc as well as the cable. You can also try a differant cable if you have one or can borrow one to rule it out.

That "red white green and blue" block is a color pattern tester. that means the monitor is on, but is not receiving a signal, so its running tests. If your monitor has Digital input and VGA input, you may just need to switch inputs. Look for 1 or VGA if youre using the blue hook up. look for 2 or digital or dvi if youre using the larger white hook up. Some monitors also have 'auto detect'. If you are in "auto detect' bbut the color box is still there, then your monitor is not receiving video signal from the computer. It could indicate a bad cable or no signal being sent by the machine. If you try another monitor, you can see if the machine is working. I would try a monitor setting for VGA-1 first, since thats most common.

Here is something you may or may not have tried:
With the HDMI cable hooked up to your TV set, reboot your computer. in many cases (even though it may be shown as hooked up) the video card will not send a signal on a specific output unless there is something plugged into it on bootup. Once that has been done, verify that you are on the proper HDMI setting on your TV. Many TVs have multiple HDMI inputs, so it is possible that there is a signal and it's not switched to it.

Sometimes its about going to the basics.

Cheap CRT monitors can be picked up at Thrift Stores, quick and cheap way to test your computer output.

This sounds like the monitor is not reading a signal from the computer. I had the same problem when I installed a DIV cable from my old VGA cable. The video card was still sending the signal via VGA port instead of the DVI port of my video card. You should cheack the cable to you're computer and what port is being used. If everything is hooked up correctly then there might be a problem with the cable. Other then that it could be you're video card. If the hard drive is running and everything is running fine then what I said should be whats wrong. If nothing works go back to the shope and tell them the new problem you have.

When you switch the monitors, do you still use the very same vga cable? If you don't, then it's time to change the monitor. When it turns on and off inmediately it means that it's receiving the signal, but that's it. If it's brand new, exchange it.

check all power cable. check vga cable,

You need to change the input signal, get into the menu on your monitor and change the signal from rgb to dvi, hdmi or vga dipending on what cable you using for connection.
There is NO rgb connector on that monitor

Good luck