My lg recorder will not delete progs !?

my l g hard drive recorder/dvd,suddenly would not delete programmes that i wanted to edit ,also the timeshift would not work,but i could still record ok,and i had a few hours space left on the hard drive .so i copied to disc my favourite stored programmes ,about 3 discs,and put them to one side .
i tried then to format the complete hard drive ,but it didnt do anything !so i put it on record for 7hours on sp,then i stopped recording, and tried deleting the programme straight away ,and it did !it also cleaned the hard drive empty ! the timeshift is ok and all else is ok ,so i fixed it witha bit of my logic !hope this helps someone one day !