My SSID keeps disappearing for days at a time for asolutely no reason at all. I'm using a wireless dongle and everyone else in my house is connected via ethernet with no issues whatsoever. The routher we have is a Dlink dir-635. I can still connect ot my neighbours wireless internet but the signal quality is so low that it often disappears as well - but this isn't really the issue as I was connected to it for a couple of hours last night whilst still unable to connect oy my own SSID. I'm at a complete loss as to the reason this is happening - It's seemingly random and eventually after a couple of days or so it comes back of it's own accord. No amount of resetting or unplugging the router does anything to help. If you have any ideas please let me know!