So, here is the problem...
Recently my _NEC DVD+RW ND-5100A stopped recognizing a bunch of discs. It seems to ignore Region 2 DVDs, DVD+R DVDs that I burned using this drive and worked previously, DVD-R DVDs that I burned on another drive, but used to play fine on this drive, and possibly some CDs, though I haven't sufficiently tested that to be sure. But, it seems to recognize and play Region 1 movie DVDs just fine.
When I say that the drive ignores the DVD, that is just what it seems to do...when I insert a disc and attempt to access it, I get one of two error messages "Cannot Access Drive D:" or "Please insert a Disc". I also get two different behaviors while inserting discs, sometimes I get the "five clicks" sound and then it seems to give up on the disc, sometimes it makes normal reading noises, but still doesn't let me access the contents of the disc.
Also, I put a Region 2 movie DVD in the drive and attempted to change the drive setting to Region 2, and that didn't work, either...it said I must insert a Region 2 disc...not very helpful.
I have not flashed or modded this drive in any way, I use CSS+Region Free Lite to get around the regional limitation (annoying, since I'm currently a North American living in the UK).
Any suggestions on further troubleshooting, or anyone seen similar behavior and sorted it out? I'd hate to have to wait until September when I'll be back in the US again to try to get the thing serviced by HP.