Don't worry, everyone was new once too. No need to apologise You'll find that MD is easy to use and you'll be obssessed like the rest of us in no time 8)
So are the N707 and the R37 the only units you're considering? I think there are other units better suited to live recording, but I don't really know too much about live recording. I'll leave that for someone else to answer :wink:
When the R37 was made, the priorities were a bit different, and so by current standards, it's big, heavy and the battery life is terrible. It doesn't have any of the newer features such as NetMD or MDLP. But it's one of the most durable units made and should last forever. It's still compatible with discs recorded on the newest units (except discs in LP mode) so in that sense, no it's not obsolete. That being said, I don't think you're going to be able to track one down. In that sense, yes it is obsolete.
The R37 will work with any computer that has a line out, because you can record from it like you would from a CD player. However, if you're asking whether it's compatible in a NetMD sorta way, no, the R37 won't work with XP because it doesn't support NetMD. From what you've posted so far, it doesn't seem that you'd need NetMD, because it's mainly for people with lots of MP3s. If you're looking for a unit which supports NetMD, I suggest you look through the T station products page because it's easier to tell which units have NetMD (even experienced MD users can't keep track of all the units)