If you had a fresh install in the past 3 weeks, I'm assuming you're a TV-only customer? I only mention because new installs of TV & broadband now have 360, not a TiVo. You can check if you're not sure.... here (you've posted with some other TV queries back in November and, at the time, had a V6)
This is often indicative of a box without a working 'net connection. On the front-left of your TiVo there's a series of green lights. Second from left, next to a painted heart symbol, is the one to check - is it on solidly, or flashing? Can you use OnDemand services ok?
Both of these are ways to check the onboard net connection, which is separate to your home broadband, is working.
On the assumption that a TiVo with these symptoms has a working 'net connection, then this should be easily solved by following Home > Help & Settings > Settings > Network > Connect to Virgin Media services now.
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