Won't boot suddenly will not boot up. Screen is black, power & battery lights are blue, num lock and scroll lock are blue, caps lock is flashing blue - but just does not start up

That is a security configuration on HP Laptops, depending on the way they blink is the problem your machine has.

Here is the web page where this info is posted, in case you need more info, hope this helps you to determain.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01443366&lc=en&dlc=en&cc=uk&lang=en&rule=26781&product=3816592
This document pertains to HP Notebook PCs with the HP Unified Extensible Firmware Interface (UEFI) beginning in late-2008. On startup, you may see a blank screen. If the diagnostic utilities detect a specific problem with hardware components, the fan turns on, but the screen remains blank. To help identify the cause of the problem, various LED lights on the keyboard blink a series of codes. The diagnostic utilities use the LEDs near the Num Lock or Caps Lock keys to blink a series of error codes. At the end of the series the blinking stops. The pattern of blinks will occur any time you attempt to start the computer until the error is resolved. Battery power LED blinks The Battery power LED indicates the condition of the power supply. When starting the computer, or when the computer is in operation, use the chart to identify the power condition. Battery Power LED Component Tested Error Condition Battery power LED off, and Caps Lock/Num Lock off Battery or AC Adapter AC adapter not connected or failure

Battery low charge or failure Battery power LED blinking Battery Insufficient charge on the battery When new computer is used for first time, the white LED light for the AC power connector blinks. Battery is still in "Shipping Mode", the light continues to blink even when AC power is connected.

To resolve, turn off notebook, connect AC power and allow battery to charge for at least 30 minutes, then start computer. LEDs near Caps Lock and Number Lock keys blink when starting notebook The LED lights near the Caps Lock and Num Lock keys will blink if an error is detected during the start up process. The LEDs will blink a number of times in a sequence and then stop. The number of blinks in the sequence indicates what component caused an error when it was being tested during start up. If the LEDs stop blinking and the computer does not start, you can press the power button again to repeat the tests. Count the number of blinks, and use the chart to identify the error condition. Knowing the number of blinks is helpful when you contact an HP support agent for technical help. Caps Lock/Num Lock LED Component Tested Error Condition LEDs blink 1 time CPU CPU not functional LEDs blink 2 times BIOS BIOS corruption failure LEDs blink 3 times Memory Module error not functional LEDs blink 4 times Graphics Graphics controller not functional LEDs blink 5 times System board General system board failure LEDs blink 6 times BIOS BIOS authentication failure

step one, big battery out? skipped that?
step 2, a good power pack , that means 19vdc on those 2 pins.
bingo BIOS screen now work ,yes?
step 3, try an external VGA screen at the P15 VGA jack there
screens work now (BIOS first) yes/no?

remove DVD, drive
and all USB devices
there booting with only 1 memory stick. (got more?, try each 1 by 1)
black screens of *****'.

the lack of flash codes, Implies Power pack is dead. or CPU overheated, and selfshuts down. that fan going dead tells
me the power park is dead.

http://pcdied.com/#black-screens

Number of Blinks or BeepsLocation of Blinking LEDsComponent Being CheckedError ConditionContinuous glowBattery power LEDBatteryThe AC adapter is attached and the battery is charging, but does not yet have sufficient charge to power the notebook.1Caps Lock/Num LockCPUCPU not functional2Caps Lock/Num LockBIOSBIOS corruption failure3Caps Lock/Num LockMemoryModule error not functional4Caps Lock/Num LockGraphicsGraphics controller not functional5Caps Lock/Num LockSystem boardGeneral system board failure6Caps Lock/Num LockBIOSBIOS authentication failureContinuous blinkAC power adapter LEDPower adapterInsufficient power

caps lock is memory problem indeed
try to reseat/swap the modules or use just one module
put something on it , for pressure

Well hellonihar, As far as your issue is concerned it seems to be some hardware issue. LED
Component
Error Condition
Blinking battery power LED
Battery
Insufficient charge on the battery
Blink: 1 - Caps Lock/Num Lock
CPU
CPU not functional
Blink: 2 - Caps Lock/Num Lock
BIOS
BIOS corruption failure
Blink: 3 - Caps Lock/Num Lock
Memory
Module error not functional
Blink: 4 - Caps Lock/Num Lock
Graphics
Graphics controller not functional
Blink: 5 - Caps Lock/Num Lock
System board
General system board failure
Blink: 6 - Caps Lock/Num Lock
BIOS
BIOS authentication failure

replace the complete key board and mouse kit

Put the RAM back in or check the RAM in securely

If the Num lock is lit constant, and the Caps Lock and Scroll Lock keys are flashing, the system is reporting a memory error. Power off the system, remove the battery, and follow the user manual from support.dell.com to reseat the memory module(s). If the error persists, you may need to replace the memory and/or the system board of the portable.

sorry to let you know sounds like hard drive is shot.........

sounds like your motherboard fried