[MovedGoalPosts]

You have strictly followed this procedure:

Power off everything, PC, router, modem.

unplug USB and ethernet cables from modem

connect only ethernet between router WAN and modem

connect PC(s) only to router LAN (ethernet or wireless)

Power on modem (let settle)

Power on router (let settle)

Power on PC(s)

It's easiest to get the wired connections running over a router first, then add in the wireless. The reboot of modem is critical whenever you swap devices directly connecte to it and as stated above, you cannot connect using ethernet and USB to the modem at the same time. Since Virgin Media don't "support" routers, they won't help you with the configuration. If you really doubt the modem ethernet port is working correctly, connect a PC direct by ethernet to it (no USB) and reboot all. If that fails then call faults (don't mention the router, just that you can't connect by ethernet to the modem).