Your cable modem should have three things running to/from it:
1) Power cable
2) Coax cable from your Virgin Media cable outlet
3) Ethernet cable from the modem's Ethernet port to your PC's Ethernet port
You need to connect the modem's Ethernet port to the WAN port on the router, using the Ethernet cable, instead of connecting it to the PC.
Then you can connect the PC to the router wirelessly - assuming the PC has a wireless interface?