Can't burn dual layer DVDs any longer

[Sheriff Hobbes]

Hello,

I have a strange problem with my DVD burner.
I have an LG CH08LS10 burner, which is not even 3 years old. I don't burn often, but I've burned many DVDs with it w/o any problems. After a pause of maybe 3 months I wanted to burn a DVD again, but the data verification after the burn process failed (I always do a CRC check afterwards, comparing original with burned content). I burned 4 DVDs in total, all went to the trash can.

I've changed absolutely nothing in my environment: same OS (Vista), same burning software (Nero), same blank DVDs (I used them from the same stack as last time!). The problem only occurs with dual layer DVDs! I can still burn single layer DVDs with passed CRC check. LG firmware is latest, it hasn't changed for years.

Any ideas? I don't know what to do, I need to burn to free some disk space.

Thanks,
Sheriff Hobbes