Upon Power Up - HD Spins, Fan Runs, Screen Remains Black, Cap Lock Light Blinks

[impedance1976]

Laptop: HP Pavilion, Mod#: 15-CS0073CL, S/N: 5CD8175XTY, ProdID: 3TU13UA#ABA.
Problem: computer has worked fine for 13 months, then yesterday when I turned it on, it sounds as though the harddrive starts and the fan definitely runs; however, the screen remains black. The power light is illuminated continuously; the "Caps Lock" button blinks in the following pattern: 5 normal blinks, 3 very fast blinks, no blinks for 2 seconds, this pattern continues as long as the computer is powered up. No other lights are illuminated.

I have not installed any new hardware of software recently.

I have tried the following (none of which worked):
(1) Disconnected AC adapter from the laptop (I cannot see any way to disconnect the battery); Press and hold the power button for 15 seconds; plug in the AC adapter; Power ON the laptop.
(2) Restoring the BIOS with Key Press Combination "Windows + B keys".
(3) Resetting the CMOS with Key Press Combination "Windows + V keys".
(4) Installing BIOS recovery file from the HP website using a USB flash drive; I was able to install the BIOS recovery file on the USB; however, when turning on the computer with the flash drive plugged in and key press combination "Windows + B keys", it did not work. Also, did not work with key press combination "Windows + V keys".

[WAWood · Accepted solution]

@impedance1976 

While I appreciate that you did a LOT of testing on your own, this is probably not related to the BIOS.

Most likely, the PC is experiencing a major hardware failure -- this is especially true if the CapsLock key is blinking or there is beeping.

Since the PC is a laptop, this HP thread describes the different blink and beep codes: https://support.hp.com/us-en/document/c01732674?jumpid=reg_r1002_usen_c-001_title_r0001

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If you CAN, to find out the problem, you would need to be able run hardware diagnostics by pressing the Esc key repeatedly and then, when the HP Startup Menu appears, select Diagnostics (usually F2) and let it run.

If you can NOT do that, or if that does not work, then there is NOTHING more you can do by yourself -- and there is NOTHING we can do because we have no way of accessing your PC from here to run diagnostics or repair hardware.

You will need to have the PC physically examined in a service facility by folks that can run their own diagnostics to determine what is wrong with it.

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If your PC is still under the original one-year HP warranty, or if you have purchased an extended warranty from HP and this is still valid, then having HP do this is an inexpensive option for you. In that case, you should contact HP Customer Support to see about having it repaired or replaced under warranty.

To contact HP Support see the following link to create yourself a case number, then call and it may help speed up the call process:

Step 1. Here is the link: https://support.hp.com/us-en/contact-hp
Step 2. Enter Product number or select to auto detect
Step 3. Scroll down to "Still need help? Complete the form to select your contact options"
Step 4. Scroll down and click on: HP contact options - click on Get phone number

Case number and phone number appear.
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If your PC is no longer under warranty, then it will cost you up front to have HP examine your PC. If you want to do that, you will have to contact an HP Repair or Service Center to see if they can examine the PC to determine the cause(s) of the problems, if it can be repaired, and an estimate of the repair costs.

If you live in the U.S., here is a link to the HP Service Repair Centers:
https://www.service-center-locator.com/hp-hewlett-packard/hp-hewlett-packard-service-center.htm

If you live outside the U.S., here is a link to HP Service Centers, by Country/Region: https://support.hp.com/in-en/service-center

Good Luck

[impedance1976]

Thanks much for all the info! Since the computer is out of warranty (by one month) and I was not able to run the hardware diagnostics, as you suggested I will take it the local computer repair shop.