I have had this DVD recorder for about a year and a half and it has been a superb recorder. All of a sudden it says it can't read my DVDs. I am using Memorex DVD+R and the same or the Staples brand. Should I change to the -R maybe? I have to go through about 4-6 DVDs before I can finally get one to record. Then most of the time it will not finalize. Does this need some firmware or something like that to upgrade it or does it have some worse problems?