HP Envy x360 windows 11 - USBC Thunderbolt stopped detecting External Monitor - solved

[Deuchar]

NEW HP envy x360, I initially had 2 monitors connected, 1 via HDMI directly, the other via a HDMI to USBC thunderbolt lead.  Was working perfectly for a month then last week a friend who was disgusted with my spaghetti junction of cables plugged into my laptop suggested I used my old  Dell WD19 Dock who he ensured was compatible.  So I gave it a go Friday and it worked perfect,  Then this morning (Monday) when I switched on my laptop the dock seemed to work fine with regards keyboard and mouse and power but didn't detect any monitors connected to it.  So to try and get some work done I quickly ditched the dock and went back to my original cable city setup, however now it only detected one monitor connected to the HDMI not the one connected to the USBC Thunderbolt.  I spent a few hours trawling the web trying every solution out there, including deleting graphics card driver and re-installing.  Ended up getting my friend who suggested I use the dock to spend a few more hours on it this evening (he must have felt guilty)  Being a bit more IT savvy he tried a whole load of fixes, and eventually found, Settings - Windows Updates - Advanced Options - Optional updates.  He said there was a big list so he just selected everything and clicked install, so we are not exactly sure what fixed it but its working now anyway, and I am back using the Dell Dock.  Hope this helps someone, very frustrating day!