Is it possible to use another all in one as a second monitor for an all in one

[bobb4]

My original 3 in 1 27" HP is nearing its end! 

I'm wondering if I can salvage part of it, the monitor, as a second monitor for the new 3 in 1?

Thx

Bob

[BeemerBiker]

You did not list your product ID

I assume you mean HP all-in-one 27

Some of the AIO had HDMI input so you can connect an HDMI cable from your new AIO to the old one

If it does NOT have an HDMI input then you can project your screen onto the old AIO as explained here
https://www.techadvisor.com/how-to/laptop/laptop-second-monitor-3674679/

What is happening to your old HP?  I can make some other suggestions

[bobb4]

It appears that my HP all in one 27" a-109 only has the HDMI input. The computer is 5+ years old. Most of the time, it is very slow loading up and running some of the programs. I have 1 TB SSD - with 350 GB used and 570 free. I have run various programs to clean up and optimize the files. I use MS defender antivirus as well as Malwarebytes. The processor is incompatible with Windows 11, which I would like to have. I use an old ASUS 22" monitor for my second screen. If I buy a new all in one, 27". it would be nice to have my present one as a 27" monitor.

Thanks for you help. Any suggestions are appreciated.

[BeemerBiker]

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@bobb4 wrote:

It appears that my HP all in one 27" a-109 only has the HDMI input.

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I think you mean HDMI output only.

You can use  the old 27" AIO as a second monitor via Wi-Fi.  However, lag due to Wi-Fi would make it unusable for gaming. 

Where the following references Laptop, just substitute your old 27" AIO

https://www.techadvisor.com/article/731314/how-to-use-a-laptop-as-a-second-monitor.html

There are possible upgrades to your system as listed below

https://support.hp.com/rs-en/document/c05246745

I had win11 running on an i5-2400 using method 3 and  it ran ok even with old Intel CPU graphics.  Your 27 a-109 has the superior NVidia chipset.