Do a search for "thomson 6300 flashing fault" and you'll find plenty of people with the same problem and I'm sorry to say that it's fatal. Mine was the same.
I was in a big ASDA this morning (21st April 09) and they had a very big pile of 6300-16 (160gig) recorders at £50, including 6 months of Setanta and 1 month of TUTV. On closer inspection each box had a sticker on the side saying it was "reconditioned as new" with a 6-month guarantee. There were at least 20 on display in this one store alone, so I think it's safe to say that a LOT of 6300's have been sent back to the manufacturer.
Thomson must know there's a problem. Whether they'll admit it or not is another story.
Mine is heading for the bin and I'm going to spend a little more on something more reliable.
cheesed off 6300 owner, April 2009