Are you talking about a freesat box or a sky+ box?
I'm not aware that Thomson made freesat boxes.
Thomson did and still do make sky and sky+ boxes, so perhaps this thread needs moving into the sky+ forum?
It's not a "DV3" that's not the model number. That logo is actually meant to be "DVB" which stands for digital video broadcasting, and just about every digital receiver has that logo now. you will find the real model number on the bottom or back of the box. If it's Thomson, the model number usually starts "DSI..."
You can format the hard drive from the installer menu (Services 4 0 1 select) and to a "full system reset" but that will of course wipe all your recordings.
If that doesn't fix it, it's either a faulty hard drive or a faulty power supply, Thomson boxes are well known for poor quality capacitors that fail and cause all sorts of problems.