When switched on Fan runs but the screen is blank!

[TantoBeach]

Computer fan and hardesk were replaced recently.
Suddenly When turning on, although a sounds comes from the all-in-one desktop, the screen is blank..

What could be the issue and what I need to do?

[Bill_To]

Greetings @TantoBeach 

Welcome to the HP Forum.

Is your PC in warranty?

Your MB is getting some power as you hear startup sounds and fans are spinning.

But you have no video out to the HP AIO integrated monitor.

Do you see any keyboard/mouse LED activity (if applicable) when you start the PC?

It's tough to determine if the PC can POST since you have no video output. You could try an external monitor if your PC supports video out to an external device.

Basic Troubleshooting Tips:

- Disconnect the PC from AC Power. Depress and hold down the power button a few times to drain residual MB power. Start the PC again.

- Check for any unusual external power supply LED activity. Good power should give a solid green LED.

- Is the PC providing any specific: flashing LED error codes or beep error codes?

- Disconnect the mouse and keyboard and other peripherals. Start the PC to check for video out.

I am sure there are additional basic troubleshooting tips to try; but I can't think of anything else. 🤔

Component Troubleshooting:

You would have to troubleshoot PC components at this point if none of the above troubleshooting tips fix your PC's startup issue.

The external power supply could still be an item of interest.

Many AIO PCs have most components integrated into the MB except for: RAM, storage drives, and possibly an M.2 WIFI card.

You would probably need to have a local PC tech check your PC if the PC is not in warranty. Finding the failing internal component could require swapping in, known good, replacement components to find the bad part.

Regards