Hi Tony,
Have you had any problems with recordings? It does appear to be a possible hard drive problem if you are unable to pause and rewind live TV as that is the same as recording.
How much free space is showing on your hard drive?
Recordings > Recorded > View all > It will show a percentage in the top left hand corner of this screen
You should check that the caling, especially the white coaxial is all snug and tight and free from any kinks.
One previous poster with this issue solved it because, "The white converter lead mush be a bit dodgy. Upon wiggling the cable the 360 box picture broke up. I swapped the lead for a standard f type to standard ariel adapter and that solved that problem. "
If the issue still persists arfter checking your cabling and storage then you should call 150 from a Virgin phone, or 0345 454 1111, option 2 (Faults)
When calling Faults ignore all the options and don't press any buttons then you should be placed into a queue and an agent should pick up the phone and book the tech for you.
Or wait a day or two and a member of the Forum Team should pick this up for you and help.