Have a HP omni 220-1185qd product # B2Q19AV#ABA and have message cannot upgrade due to NVIDA GT540M Graphics card not compatible. I have tried many times to get an updated driver with no success. Do you have any thoughts?
When you say you get a message it is not compatible, is that from the Getting Windows 10 App; launched from the systray? If so, then probably no driver exists right now and Windows 10 upgrade is not recommended. Nvideo does not list it on their Windows 10 driver page; the lowest being the 600 series of the GT.
I'd recommend waiting to see if a driver is produced; the free upgrade offer is good for another 9 months. There are some more extreme things you can try, but only do that if you are willing to fully reinstall or reset back to HP shipped image if it does not work.