I've got a Sagem DBox2 (debug mode) and all works fine, can get channels,

Sometimes it will just freeze up on me and requires full reboot, work for a few mins and then freeze up again - more often after a lot of channel changes.
Sometimes it can be fine all night long.
I've had a look around the forums but can't find anything useful (totally new to all this as well).
The only useful(?) info I found suggested I discinnect the modem (which I did) and it helped a little but the problem is still there.
Any ideas please?
If you need more info let me know.
Thanks in advance.