Hi Roy,
Sounds like your box is going to need replacing at some point, you could try doing a factory reset and if you have no recordings select the option to format the hard drive, you will have to sign into your apps such as iPlayer, Prime, Netflix and ITV Hub again, also Match frame rate and Standby power consumption will go back to their default settings if you have changed them.
There is also no way to get your recordings back if they have been deleted.
If / when it does it again you can either call Virgin on 150 from a Virgin phone, mobile or landline, or 0345 454 1111 from any other phone to report a fault or come back here for one of the forum team team to pick this up which might be 2 to 3 day's.
Roy.