I've got a Pioneer 540/640H-S DVD player. Most of the DVDs I'm hiring lately (checked to ensure they are clean) are getting stuck at various points during the movie; often repeatedly. Mostly, they get to a point in the movie, freeze for several seconds, then the playback stops. I can re-start, but they inevitably freeze again in the same spots. Often happening so often that the movie is unwatchable. I play them on another cheaper DVD player and they sometimes stick, but not as badly or as often. Is it my player at fault? I could accept that happens every now & then with a hired DVD, but it's happened to the last 8-10 DVDs I've hired. My player is about 2-3 years old. Is there a cleaning regime for the player itself? Could the internals require cleaning or maintenance? Any suggestions appreciated.