Thomson harddrive - just keeps jumping. ?

Got a Thompson 160GB harddrive. had a roblem with a programme i had saved but couldn't watch, or delete, this is when the jumping/jittering problem started. managed to eventually delete the programme, have tried re-scanning. have unplugged it for a week, tried a reboot, even plugged in a signal booster to try and improve it but to no avail. andy ideas? has anyone please got a solution?