Unwanted multiple recordings?

I've had a PVR-9300T for a couple of years with only minor problems (freezing). But receintly, after an on screen instruction to retune for more channels, I find when I record something, it makes perhaps 15 or 20 copies of the same program. It also gives the program an incorrect title / date and sometimes changes title / date of things recorded ages ago. Any one got any ideas on a solution? It takes ages to find gardners world! Thanks.