It does. You have to enter your DVD-key when you install the game and then it will "call home" the first time it is run. However, there might be an explanation for your lack of DRM - are you, perhaps, from Russia or the owner of a Russian copy?
Well, the SecuROM driver might need to be re-installed by NWN 2, something that would likely happen the next time you inserted the disc and ran the game, but other then that nothing that I can think of.
Not that I know of, but you can use this tool to completely remove it from your system. As for the game, I'd buy it - Mass Effect is worth $20 and I would recommend getting the sequel when it comes out as well if you enjoy the original.