Can't connect old monitor to new laptop - DP to HDMI cable

[Spencer77]

HP Compaq LA2405x - I have tried a new DP to HDMI cable to connect it with my new laptop.

My new laptop does not detect any display. The display works on my old laptop (which was DP to DP cable).

Help!

[TheOldMan]

Since you do not mention the laptop model number, let's just assume you are using the HDMI output port on the laptop. 

I looked at the HP Compaq LA2405x monitor specs.  It has :

One VGA connector; one DVI connector; one DisplayPort connector. - no HDMI input.

The next assumption is the cable in the post "DP to HDMI cable to connect it with my new laptop."

Please look at this page

https://helpdeskgeek.com/help-desk/displayport-to-hdmi-not-working-9-fixes-to-try/

Note in that  - "A DisplayPort to HDMI cable is not bi-directional. It’s designed to work as an output device, which means it allows you to connect a DisplayPort-enabled computer to an HDMI input."

"A common mistake is to assume that any cable with a DisplayPort plug on one end and an HDMI plug on the other can will work in both directions. It’s important to double-check that you’ve bought a converter designed specifically to convert the output you’re using to the desired input."

What is needed is an active HDMI to DisplayPort Adapter IE: https://www.amazon.com/Cable-Matters-DisplayPort-Adapter-Resolution/dp/B00JQORLCG/ref=sr_1_19?dib=ey...