Dell Inspiron 1420 Notebook PC?
The white screen can be fixed. How?
Connect a VGA monitor to the laptop. Connect to the VGA port on the right rear. Example of a VGA Cable, and VGA connector,http://en.wikipedia.org/wiki/VGA_connector
You can use a CRT type monitor, (Looks like a small TV), or a flat LCD screen monitor that has a VGA cable.
By default the display should show on the external VGA monitor.
Press, and hold the Fn key down, and at the same time tap the F8 key ONCE.
There are at least 3 display options available;
1) Internal monitor of laptop ONLY
2) Internal monitor of laptop AND external VGA monitor
3) External VGA monitor ONLY
Hold the Fn key down again, and tap once more on the F8 key.
No display on the external VGA monitor, means you have a bad graphics chipset. Replace motherboard.
Display does show on the external VGA monitor, means you have a problem with;
1) Video Cable
2) Screen Inverter
3) LCD screen
The Display Panel Cable (Video Cable for Dell), connects to the motherboard by the left Hinge.
Goes under the left Hinge, and up into the Display Assembly.
It then connects to the Screen Inverter, and to the back of the Display Panel. (LCD screen for Dell)
From normal opening, and closing of the laptop, the Display Panel Cable may become pinched in the left Hinge.
This can cause;
A) The connection at the motherboard to come loose
B) The connection at the back of the Display Panel to come loose
C) Stretch the wires inside the Display Panel Cable's sheath, and damage the wires. (Break)
If you are lucky just the connection at the motherboard, and/or connection at the back of the Display panel, may have come loose.
Diagnoses is to NOT just look at the connections, but physically push the connectors of the Display Panel Cable, into the connector at the motherboard, AND back of the Display Panel.
Visually inspect the Display Panel Cable's sheath. Do you see any outward appearance of damage? This means the tiny wires inside may be damaged.
Replace the Display Panel Cable.
Remove ALL power. Remove the AC adapter (Charger), and Battery.
Remove the Keyboard Cover.
Unfasten the Keyboard, LEAVING the Keyboard Cable ATTACHED to the motherboard. Roll the Keyboard over, and lay it upside down on the Palm Rest Cover,http://support.dell.com/support/edocs/systems/ins1420/en/SM/display.htm#wp1129771
Two Philips head screws at top of Keyboard. After removing, lift the top of the Keyboard up a little, slide it a LITTLE towards the Display Panel.
DO NOT lift it straight up at first.
There are 3 plastic tabs on the bottom of the Keyboard, that slide into the Palm Rest Cover. If you pick it straight up you will break those tabs off ]
In Removing the Display Assembly, note where number 1 points to.
This is the Display Panel Cable's connection, TO the motherboard.
Note where number 2 points to. Those cables going to the Mini-Card Antenna, HAVE to be reconnected, right back to the SAME terminals on the Mini-Card. Make a mark on the cables, and matching marks on the Mini-Card.
Use the instructions in Removing the Display Bezel.
Use the instructions in Removing the Display Panel.
View the last illustration in Removing the Display Panel.
Note how the Display Panel Cable attaches to the Display Panel, and Screen Inverter
Number 2 points to the connection at the back of the Display Panel
Number 6 points to the connection to the Screen Inverter
The Black connector that is not numbered at the bottom, is the motherboard connector of the Display Panel Cable.
This is a better view of the screen Inverter,http://www.ebay.com/itm/Dell-Inspiron-1420-1421-LCD-Inverter-Backlight-Combo-/370274752470
Display Panel Cable checks out? Look at the screen Inverter. This small circuit board is located at the bottom of the Display Panel, and behind the Display Bezel. Closer look at link listed above.
Is the cable coming from the Display Panel Cable, plugged in tightly to it?
Does the screen Inverter look damaged?
Post back in a Comment, and we will go from there.