My dvd recorder keeps ruining blank dvd+r's.

When I first learned to record on my dvd recorder [a few months ago], it seemed to do a fairly good job, although the playback was a little fuzzy. However, recently the player/recorder has been behaving in an odd fashion. Sometimes it does not recoginize a disk in the tray, even a commercially pre-recorded disk. Other times it will call a disk a 'bad disk' one time, then, after I open and close the tray, will indicate there is 'no disk' in the tray and the next time and play the same disk. This even occurs with commercially pre-recorded disks. The player/recorder has also begun stopping in the middle of the formatting phase, thereby ruining several blank disks. Or, occasionally, it will apparently format a disk, then record one or two things before refusing to further record on it, calling it a 'bad disk' and asking me to put in a recordabe disk when I press the record button. It has ruined between 5 and 10 disks in very short order. I haven't been using this player very long and am not very happy with this poor preformance. Any suggestions? [I have tried a cleaning disk a couple of times without apparent benefit.]