wow old fogies and new technology
not like my dad then, he wont touch anything thats been invented after 1960 lol
a bit stuck in his old ways..
of course whenever he does use something new, there is always the comment that follows
"well its OK, but its not as good as they used to be, back then things were british made and better quality"
when he sees an old car on the road he says, look at that that brilliant that, better than all these new cars??
i know which i would prefere to drive 200 miles down the motorway lol
anyway, back to the subject at hand

the worst thing it could be is the hard drive is on its way out
but if it only been doing it since the upgrade, then it sounds like a software problem..
you could try unplugging it from the wall for a few mins.. note that when pluggin it back in you will have no response from the remote for a minute or 2
or force the box to update the software....
Switch of mains to the box, depress the backup button on the front panel of the box (not on the remote), keep the button pressed whilst switching on the mains again, keep button pressed until 4 LEDs are lit on the front panel, message appears on TV saying updating software, process is complete after about ten minutes when the box returns to stand by mode. If problem continues straight away repeat the process as software updating doesn’t always do the trick first time.
Lets hope the software update does the trick!