I'm having this issue as well with my 722N that I just got 2 days ago. It worked fine for the first two days, and now my computer does not recognize it, right now I'm using a small D-link adapter which works fine in all of my USB slots, and worked fine for the week or so that I spent waiting for my 722N to come in the mail.

I had an 822N before this which began having this same issue, but I disregarded it as it just reaching it's death as it had become incredibly sketchy nearing the end of the four or so years that I had it(it would occasionally stop working, and I would have to spend 5 minutes unplugging and plugging it back in, in order to get it to work.)

One thing I noticed in both cases, is that when it stopped working, and I went to unplug it, the computer would BSOD the moment it got unplugged. My computer practically never BSODs normally.

any help would be appreciated

I got this instruction from TPLink customer support:

There are maybe some block from your computer,please get into Windows safe mode,here is the instruction that you can follow.
http://www.tp-link.com/en/article/?faqid=791

I went into safe mode and noticed in device manager that TPLink adapter was disabled. Rightclick and enable + reboot comp did the job.
Hope this helps!