Compaq CQ57 410US screen won't power on.

Assuming the unit is plugged in, this could be an issue with the power supply, or an issue where the cord connects to the laptop. If the power connector on the back of the laptop is secure / doesn't feel loose or damaged, you may want to simply get a replacement power supply from a local electronics store. Be sure to take the make and model information of the laptop and the power supply with you to the store.

Do you see anything on the screen? Does the HDD LED blink? You can start by removing the HDD and testing it or have it tested.

2 causes: wrong screen or bad connection between display and motherboard. Click here for more help

Do you have an Anti-Virus program installed on your PC? If so, can you try and disable it before you print.

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Dear Chris,

Seems like a bad RAM. Simply change your RAM and then give your laptop a go and it shall be all fine and smooth sailing on wards. You can test it by simply borrowing a RAM from your friend for a while. But do make sure that RAMS are of same type.

If you already replaced the motherboard then try replacing the power cord. If you meant you replaced the cord already, the it might be your motherboard is bad.

When you press the power button do you hear the fan running, hear the disk drive running, see any lights, do you hear the cd drive click once and see the light come on briefly on the cd drive door? If you see all the aforementioned then it is surely trying to boot. Computers don't boot mainly because of the following problems. 1) Bad Power Cord or Power Supply. 2) Electro Static Buildup. 3) Bad Motherboard 4) Bad boot or system files.
Remove the Power Cord and the battery if it's a laptop. Press and Hold the Power Button for 30 Seconds. Then replace only the Power Cord and try hitting the Power Button. If it boots you had an Electro Static Buildup. If you have boot or system files that are missing or corrupt normally the system will be telling you that on an error message that appears on the screen. Does your system show you anything on the screen when you press the Power Button? If not you have a Power Supply or Motherboard issue.

It's a sign of RAM failure. Replace your RAM.

First see if the power on self-test (Fn+ Power) or the LCD BIST (D+Power) will run. The Diags are normally on a blue screen with white test, the LCD BIST is simply 4 Solid Color Screen looking for defects in the LCD panel.
If you hear beeps/windows sounds when the system boots and the LCD BIST test does nothing then the LCD has likely failed and you will need a new one. You can try an external monitor and see if you get video on an external screen.
If you don't then try these steps:
http://www.fixya.com/support/r3581893-how_to_troublehoot_a_portable_compouter_

There are a few possibilities as to what's causing this problem.
First, there may be a problem with the screen's backlight, either with the bulb itself or with the power inversion board. This can be repaired fairly easily with a little time and care.
Second, and more catastrophic, there may be a problem with the graphics processing unit (GPU), which would render the laptop totally useless.
Third, if some other component came loose (RAM, wireless card, hard drive) and is no longer connected properly, most systems will refuse to boot. This is obviously the easiest problem to fix.
The easiest way to test whether your laptop is actually still running or if it's burnt out is to make sure it's completely shut down, connect an external monitor, and power up. If you see the computer's start-up splash screen or BIOS diagnostics, then the problem lies with the screen itself.
If you don't see anything on screen, don't hear any beeps or sounds from the computer, or can't toggle CAPS LOCK or NUM LOCK, then it's more likely that there's a hardware problem. If you've checked all the connections for the above mentioned components, then some component may have burnt out and would need replacement. In that case, your best bet would be to physically take the laptop to a repair center, such as Best Buy's Geek Squad, Staples' Easy Tech, or any of your local computer repair centers, and have them run detailed diagnostics on it. If your laptop is still under a service plan, send it in to HP and have them fix or replace it.