2 Problems: external screen & background light

[Kat10Col]

Dear all, 

I have two problems with my new HP Laptop (Probook): 

1st: my older external screen (Asus) does not work with my new HP Probook/ Win11. - Identification does not work. But it worked perfectly with my old laptop and Win10. It ist connected by HDMI.

2st:  the button for background light on the normal screen is grey shaded and does not work. Additionally, the "light sign" on the laptop keypad (button F3-F4) does not working. The screen shows all the time bright light. 

I am not an expert, only a normal user. I am not expericend in programming, so I need "easy" answers/ ideas for support. 

Thanks from Germany! 

[Samrit26]

Hello,

Thanks for the clear explanation — I’ll keep this simple, step-by-step, and non-technical, and I’ll explain why each thing matters. You’re not doing anything wrong 👍

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Device context

You have a new HP ProBook with Windows 11, and:

1. An older ASUS external monitor does not get detected via HDMI

2. Screen brightness cannot be changed (slider greyed out, F3/F4 keys not working)

👉 These two problems are connected and have the same root cause.

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✅ The real cause (important)

Your laptop is missing proper graphics and system drivers.

When this happens in Windows 11:

• External monitors are not detected

• Brightness controls are disabled

• Keyboard brightness keys do nothing

• Screen stays at maximum brightness

This is very common on new HP laptops, especially if:

• Windows 11 installed drivers automatically

• Or the laptop was set up without HP drivers

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🧩 Problem 2 first (brightness) – easiest to confirm

The brightness slider being greyed out means:

❌ Windows is using a basic display driver
✅ The Intel or AMD graphics driver is missing

This must be fixed first, otherwise HDMI will also fail.

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Step 1 – Check graphics driver (very easy)

1. Right-click on the Start button

2. Click Device Manager

3. Open Display adapters

Tell me what you see:

• ✔️ “Intel UHD / Iris Xe” or “AMD Radeon” → OK

• ❌ “Microsoft Basic Display Adapter” → this is the problem

If you see Microsoft Basic Display Adapter, continue below.

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Step 2 – Install HP graphics driver (most important step)

Do not use random websites.

1. Open your browser

2. Go to: support.hp.com

3. Enter your exact ProBook model
   (example: ProBook 450 G9, ProBook 445 G10, etc.)

4. Choose Windows 11

5. Download and install:

   • Graphics driver

   • HP Hotkey Support

   • HP System Event Utility

👉 Install them in this order
👉 Restart the laptop when finished

💡 These drivers control:

• Screen brightness

• F3 / F4 keys

• External monitors

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🖥️ Problem 1 – ASUS external monitor not detected

Once the graphics driver is installed, HDMI usually starts working immediately.

After restart:

1. Plug in the ASUS monitor with HDMI

2. Right-click on Desktop → Display settings

3. Click Detect

If it still doesn’t appear:

Easy checks

• Try a different HDMI cable (older cables often fail with new laptops)

• Try another HDMI input on the ASUS monitor (HDMI-1 / HDMI-2)

• Make sure the monitor is set to HDMI input (using monitor buttons)

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Why it worked on Windows 10 but not Windows 11

Windows 10 was more forgiving with older monitors.

Windows 11:

• Requires proper GPU drivers

• Does not enable brightness or HDMI without them

So this is not your monitor’s fault.

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🔒 What this is NOT

❌ Not a broken laptop
❌ Not a Windows 11 bug
❌ Not a hardware defect

It is missing HP drivers, nothing more.

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✔️ Expected result after fixing drivers

• Brightness slider works

• F3 / F4 keys work

• External ASUS monitor is detected

• Screen no longer stuck at full brightness