Number 1: Could be a number of different problems, it may actually be bad ports... Does this issue happen when anything else is plugged into the USB ports (e.g. other mice, keyboards, etc)? After doing some searching, it appears that the Naga not being detected is a pretty common issue, unfortunately I haven't been able to find a fix yet. I'll keep looking and post again if I find one.
Number 2: That's a fairly well known issue with the Naga, a piece of plastic gets worn down and stops clicking correctly... There are a number of tips/tricks on how to fix it, this is the one I normally recommend:
http://www.youtube.com/watch?v=xIR3MfrD7Gc
Edit: These sorts of problems are exactly why I don't recommend the Naga (or newer Razer peripherals in general) to anyone. Razer has "sold out" and are producing mice with obvious design/material problems, and have been for a couple years now... Instead of fixing the problems, they just continue to sell them because they know people will buy them... I'm not sure why, after 6 mice, you continue to purchase them, but I'd suggest checking out the
Logitech G600 or
Corsair M90 next time, they're both MMO mice and they both are reportedly much more reliable than the Naga.