The first thing you could try before all that or after, preferably first, is to take out the battery and try plugging the charger in the laptop to supply in a more direct power. Then turn it on a see what happens.

Can you get to BIOS? Anyways.

1. I am going to assume you have Windows 10. After turning on the laptop, keep pressing “F8”
2. This will get to “Safe Mode” afterwards, go to “Troubleshoot”—- if you can get to Safe Mode thats a great thing to know. So tell me.
3. After that go to “Reset your PC”
4. Then press “Keep my files”

Doing so should reinstall Windows and hopefully fix your issue as I would primarily want to assume some OS hdd failure as its the easiest to start with. Especially since its just a black screen afterwards.

You could also try plugging the laptop to an external monitor and see if it boots. Once its hooked up to an external monitor.

Start up your laptop, and press and hold the function key which is the letters "fn" inside a box.

Press and hold this with the corresponding F# key that has the monitor symbol, which may look like this " lOl " or some variation of that.

Some laptops vary. Could be FN + F4 or F5. Seems to depend.

Try all this and tell me what happens.

more symptoms are needed - like are your LEDs doing anything.

Based on just the fan noise - I would say it is running at full speed because the temp sensor is telling it it is hot. That might indicate the CPU is shorted out.

I had that problem on one of my laptops.

Hi Brainy! It is most likely your PSU (Power supply) You still should:

1. Check the Power Supply:
   • Power Cable and Outlet: Ensure the power cable is securely plugged in and test the outlet with another device to confirm it’s working.
   • Power Supply Unit (PSU): The sound you heard might indicate a PSU failure, especially if there was a pop or a burning smell. This can happen due to a power surge or component failure. Consider testing the PSU with a multimeter or swapping it with a known working one if you have access to one.
2. Inspect for Visible Damage:
   • Open the case and look for signs of burnt components, particularly around the PSU and motherboard. Swollen capacitors or burnt marks indicate a likely point of failure.
3. Perform a Basic Power Reset:
   • Disconnect the power cable and hold down the power button for about 15 seconds to discharge any residual power. Then, reconnect the cable and try turning it on again.
4. Motherboard Diagnostics:
   • Check if there are any diagnostic lights or error codes flashing on the motherboard when you try to power it on. Some HP desktops have diagnostic LEDs or beep codes that can indicate specific issues.
   • If the PSU appears functional but the system still won’t turn on, the motherboard itself may have failed.

If none of these steps help, the most likely culprits are a failed PSU or motherboard.

(Formatted By ChatGPT 4o-. Never written)

@fatimaezzah8117 here is what the service manual says about the 4 blink code

Power failure (power supply is overloaded).

OR

The incorrect external power supply adapter is being used on the USDT.

and here is what to check:

1. Open the hood and ensure the 4 or 6-wire power supply cable is seated into the connector on the system board.

2. Check if a device is causing the problem by removing ALL attached devices (such as hard, diskette, or optical drives, and expansion cards). Power on the system. If the system enters the POST, then power off and replace one device at a time and repeat this procedure until failure occurs. Replace the device that is causing the failure. Continue adding devices one at a time to ensure all devices are functioning properly.

3. Replace the power supply.

4. Replace the system board.

OR

The USDT power supply adapter must be at 135W and use the Smart ID technology before the system will power up. Replace the power supply adapter with the HP-supplied USDT power supply adapter.

Let us know what you find out and then we can try to fix your computer. Check the power supply first.

Here is the HP 8200 Elite Series Maintenance And Service Guide for your computer.

Hi @alvinekipn54993

If the red light is blinking, count how many times that it blinks when you first turn the PC on..

The number of blinks indicate what error has occurred.

Here's the maintenance ans service guide for the model.

Go to p.266 -p.267 to see which error code matches what is happening in your PC.

@sihlezwane there are instructions that are specifically for your system

Press and hold the power button for less than 4 seconds. If
the hard drive LED turns green, then:
1. Check that the voltage selector, located on the rear of the power supply on some models, is set to the appropriate voltage. Proper voltage setting depends on your region.
2. Replace the system board.
OR
Press and hold the power button for less than 4 seconds. If the hard drive LED does not turn on green then:
1. Check that the unit is plugged into a working AC outlet.
2. Open computer and check that the power button board cable is properly connected to the system board.
3. Check that power supply cables are properly connected to the system board.
4. Check to see if the 5V_aux light on the system board is turned on. If it is turned on, then replace the power button board.
5. If the 5V_aux light on the system board is off, then replace the power supply.
6. Replace the system board.

Check all of those things out and use the HP Compaq 8200 Elite Maintenance & Service Guide to work on your computer.

To see if the monitor is the problem, you can try connecting it to another one. If it works on another monitor, then the monitor may have some problem with the connection. Of course, you can also check the cable connection as well.

If the problem persists, you can update the graphics drivers or just call a specialist

@gauranshkushwah you re not giving us a whole lot to work with here. Going by what you wrote, this sounds like either a bad hard drive or a bad OS. You will have to check and see if you can get into your computer's BIOS and see if it does recognize the HDD. If so, then it is possible that this is an OS issue and you may have to reinstall it.

Use this 8200 Elite Series Maintenance And Service Guide to fix your computer. It does address hardware, software and troubleshooting steps.

@prernacoll27717 try this first.

Power reset your desktop computer

Perform a power reset (or hard reset) of your desktop computer to clear information from the computer memory without erasing personal data.

1. Turn off the computer.
2. Disconnect the AC adapter.
3. Disconnect all nonessential peripheral devices, such as printers, scanners, external hard drives, and USB flash drives.
4. NOTE:
5. Do not disconnect your mouse, keyboard, or monitor.
6. With the AC adapter unplugged, press and hold the power button for approximately 15 seconds.
7. After you drain the capacitors, reconnect the AC adapter. Leave peripheral devices disconnected.
8. Turn on the computer. from here

Check to make sure that the power LED does not show you a white blink at all. Next download the Maintenance and Service manual for your computer from here

Page 96 tells you what those two blinks mean:

Red Power LED flashes two times, once every second, followed by a two second pause. Beeps stop after fifth iteration but LEDs continue until problem is solved

Possible cause

Thermal protection activated:
Air flow is restricted, a fan may not be functioning, or the heatsink is not properly attached

Recommended Action

1.Clean the air vents on the front, back, or
any other vented side of the computer.
2. Ensure that there is a 10.2 cm (4 in)
clearance on all vented sides of the
computer to permit the required airflow.
3. Ensure that computers are not so near
each other that they are subject to each
other's re-circulated or preheated air.
4. If the computer is within an enclosure,
ensure that there is proper intake and
exhaust ventilation for the enclosure.
5. If a message appears on the screen
indicating that a fan is not working, replace
the fan.
6. Ensure that the heat sink is properly
attached.