Macbook is booting up, with sound but no display

Resetting the PRAM may do the trick:
You reset the PRAM by rebooting a Mac and then immediately hold down the Command+Option+P+R keys, you will then hear the Mac reboot sound again, signifying your PRAM has been reset. You must hit the key combination before the grey screen appears otherwise it won't work.

you've tried rebooting, you've reset the PRAM, you've done it all, but your Mac is still behaving strangely. What next? In certain circumstances, resetting your Mac's System Management Controller (SMC) can be a solution. This is sometimes necessary to restore normal lower level system functionality to your Mac.

Here's how to reset the SMC on any type of Mac (and any version of OS X) and the type of problems that it may resolve.
When & Why Reset SMC on a Mac? Some Common Hardware Reasons

Typically it's power and hardware related issues that can be helped or resolved by resetting a Mac SMC, particularly if you're having these types of problems:

* Issues with your Mac's cooling fans and fan management: fans run constantly at high speed, fans run high despite low CPU usage and adequate ventilation, fans not working at all, etc

* Power management and battery problems: Mac isn't turning on, sleep isn't working, random shutdowns and reboots, battery isn't charging, Mac won't wake from sleep etc

* Light problems and improper lighting management: battery indicator lights aren't working, display backlighting isn't adjusting to ambient light changes, keyboard backlights not working, etc

* Video and external displays not working: display brightness functionality not working properly, target video mode isn't working properly, external display isn't working, etc

* General performance and functionality problems: abnormally sluggish behavior despite no CPU or disk usage, external ports not working, airport & bluetooth aren't showing up, external devices are not being found, etc

So now that you've concluded you need to reset your SMC (Note that the SMC is on Intel Mac's only), here's how to do it on MacBook's, MacBook Pro's, iMac's, Mac Mini's, and Mac Pro's. Notice that the reset instructions are different for MacBook and MacBook Pro's if you have an internal or detachable battery.
Reset SMC of a MacBook Air, MacBook Pro Retina, or MacBook Pro's with an internal non-removable battery

This is how to reset SMC on most modern Mac laptops:

Shutdown your MacBook Air / MacBook Pro
Connect the power adapter to your Mac
On the MacBook/Pro's keyboard, hold down the Shift+Control+Option keys and the Power button at the same time
Release all keys and the power button at the same time
Boot your Mac as usual

Here's the key sequence to hold down:

Reset the SMC of a MacBook Air or Retina MacBook Pro

Do keep in mind that by resetting the SMC you will lose power specific settings, like the time it takes to sleep a Mac and other customizations to power settings. No big deal, but if you have made many changes to your hardware behavior you will want to adjust stuff like sleep behavior again.
Reset SMC of an iMac, Mac Pro, Mac Mini

Resetting SMC is different for non-portable Macs:

Shut down your Mac
Disconnect the power cord
Press and hold the Mac's power button for 5 seconds
Release the button
Reattach the power cables and boot the Mac as usual

Reset the SMC of a MacBook or MacBook Pro's with detachable batteries

mac reset the smc Older MacBook laptops with a removable battery can reset SMC with the following approach:

Shutdown the MacBook/Pro and remove the battery
Disconnect the power adapter, hold the Power Key for 10 seconds
Release the power key and reconnect your battery and power adapter
Turn your Mac on
Let boot as usual

Hopefully that will clear up your problems, if not it might be worth a visit to the Apple Store or a certified repair center.

Happy New Year,
Kerry

Hi,
For that problem, do this first check-up your bios setting.
Power on your PC laptop, when screen popped up ( press F2, delete etc. ) to get into standard bios Setup you see there if your hardisk drive detected or not detected. if not detected try to open your Laptop PC ( need power off. open cover at the back of your laptop ) check-up your hardisk drive for loose power cable, data cable hardisk Some burn , noise hardisk sound ) if detected, your operating system corrupted. you need to Reinstall your operating system like windows xp, windows 7 or linux base operating system. try that Solution first.

Just let me know if not yet working your laptop PC.
Regard.

Here is wher you can buy replacement hinges.. $150 (wow)
http://www.powerbookmedic.com/Macbook-Air-Display-Hinge-Set-p-17201.html

Here is their free instruction guide page
http://www.powerbookmedic.com/mac-repair.php They also have a send in repair service.

You might want to shop around for the hinges.. ebay??

Double check cable from the motherboard to your hardisk likeIDE or SATA together with the power cord
just make sure if its fully inserted. boot up the pc press delete to check UPTHE BOIS IF THE HARDISK is connected. RAM( Random Access Memory) maybe defective. replace it to thenew one and boot up your desktop. sometimes if the onboard /vga, (video graphics adpter) are defective its also beepingrapidly. also try to clean up your ram using pencil eraser.

Ensure you have hardisk and OS installed, take off any CD on CD Drive. If still won't work, try to re-seating the memory card and graphic card (if you use one in slot).
Check the Power and Data cable connection onto hardisk.

first click the start then fin run type here shutdown -a

there is no backlight or vga fault posible to fix Micromend London goop poeple

Later MacBook (Pro) use a mini-DVI connector that does not pass analog needed for composite or S-video. Was yours ever working? And most DVI connectors do not pass sound as seen by your cabling. You cannot detect display through RCA. You just set it in Sys Prefs :: Displays, try some other settings, although your seem right.
I have a white early-2009 MacBook and mini-DVI to HDMI adapter (monoprice <$10) and HDMI cable and have not connected the TOS-link for sound, yet--just slideshows at 1920x1080. You will get a much better picture digitally. -Ken

Boot from the original system DVD and try a repair from there

It seems that you don't have any Operating System installed. You need some bootable OS setup disk, and change BIOS settings to boot you PC from CD. Insert disk and restart PC, then follow onscreen instructions to setup OS.