These boxes are old now and often this error results in replacement. But there's a few things you can try.
Make sure the white coax cable is screwed in tight both at the V+ box and at the wall. Re-insert the smart card. Switch off for 10 minutes then switch back on and leave it a few hours as sometimes they take ages to boot up.
Ask your daughter to check the service status for her area to see if there's any issues. Either on My Virgin Media or by calling up.
It's also possible that if it hasn't been used for a while it's been deactivated, in which case your daughter needs to ring up and speak to faults to get them to re-activate it. Only takes a few minutes.
If after doing the above it's still not working it probably needs replacing. Your daughter can ring Virgin free on 150 from her landline and speak to faults. They'll test everything from their end and either send a replacement box or an engineer. If the box is replaced, it will be a TiVo or a V6 as V+ boxes are no longer carried. She will lose her recordings.