What do you mean by "normal virgin" if you have "upgraded" from V6 TiVo to 360 Horizon software then there is no going back, the old TiVo software has been deleted your hard drive reformatted and 360 software installed.
You could try pressing and then hold the TV and Rewind button for 10 seconds which will factory reset the 360 remote. (This has supposed to disabled with the latest software releases).
After the factory reset, try pressing TV and 0 button for 10 seconds and it should now force pairing.
You could also try putting the box into 'Pairing Mode' by pressing the Standby/On button on the front of the box for 10 seconds. Then using the 360 remote control, press and hold the 'TV' button and the '0' button together for 10 seconds. And fingers crossed hopefully a message should appear on the screen confirming that pairing was successful and the remote will function fully again.
If none of these work you might have a faulty remote and a call to Virgin might be required or wait for one of the forum team to respond which might be 2 to 3 days.
Have you also tried rebooting the box by switching the power off and on again with the switch on the back of the box.