You can try powering the box off at the mains for perhaps 10minutes and then retry.
Otherwise, a TiVo/V6 that won't bootup probably has a fault.
I'd recommend calling VM and reporting it. 150 from a VM phone, or 0345 4541111 from any other phone.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks