thanks for the info mate
yesterday I tried to clean the drive lens but nothing changed, so probably it's 100% died.
now I have to look for another system, there are some Xbox units sold as "junk" here in Japan, what worries me is that the one I'd buy has the drive effectively working...
another option, but not in the short time : I have a PAL Xbox in my home country, if I take that DVD drive and I put on my JPN system there would be problems? at lease Europe and Japan were in the same region as DVD format, so I suppose I would not have problems in doing that (considering also I use the drive just to install my games on the HDD, especially now that I realized how big the dvd drive problem is...)
damn, I bought 12 games in October and I can't play them actually >_<