Probably the power supply capacitors are going bad. This causes hum and mains interference on the low voltage supply. They`ll need replacing. Switch off the box overnight, switch on next morning. If it wont reboot, the capacitors ARE bad and must be replaced. In either case they need replacing. Take it to a local tv engineer. They will give an estimate. Or look on eBay for repaired/replacement power supplies. They are going for between £10 and £25. Cheaper than buying new!!
thomson fan, June 2012