If both the above elaborated methods didn t fix your problem of hdmi not working on windows 10 then you should try to check if your hdmi device is set as the default of not.
Hdmi to vga cable not working on tv.
Video signals may be adapted in either direction hdmi to vga or vga to hdmi but there are certain limitations and expense differences.
Problems associated with vga to hdmi cable.
Unplug the hdmi cable from your computer tv reboot your computer and reattach the cable.
Your title is saying hdmi vga adapter not working so what is it that the laptop is not working with the hdmi adapter or the system is not working need a little more clear info as being a hp laptop you can do a hard reset by holding the power button down until it shuts down then remove the battery and ac power adapter now hold the power.
You should also inspect that the hdmi ports pc and monitor tv aren t covered with debris or dirt.
The cable converts the higher standard high definition multimedia interface signal into the lower video graphics array standard.
If you haven t already swap out your hdmi cable for a hi speed hdmi cable with a speeds of at least 10 2 gbps but preferably 18 gbps.
This will refresh your hdmi connection and might fix the issue where your hdmi port is not working.
If you have an hdr enabled device such as a uhd blu ray player or streaming device connected to an hdr compatible tv it s possible that the tv is not recognizing the hdr encoded content.