I had exactly the same problem u are experiencing and none could help me, but then I realized something, My wifi card on my pc has the hotspot option so I tried to enable it, but it showed an error that the ICS service cant be started, so I tried different approaches and found that my pc had a lot of services damaged run a cmd with sfc /scannow, it will tell you, if your pc had services broken, it will not connect, after I found the error I did a fresh install of windows and voila, it worked at the first try, I was trying to find an error on my setup, ip, even on the 3ds, but all fault was of the windows OS, I know a full fresh install is too much, but if u have a way to run it on a virtual machine or on a different pc Im sure it will work.