Robbr's take on the power supply seems reasonable to me. Replacing power supplies seems to be fixing an awful lot of weird problems recently.
Flashing N, Network off, Power on usually means the Slingbox is not configured. Makes sense after a hard reset. The network light staying off even though it's connected to the router (and the ethernet cable and router are verified working) is what bugs me.
I think you've got a hardware failure. But before you give up, take it on a trip to visit a friend. See what happens if you connect it up to their router. No need to bother with video sources, just power and ethernet. You're looking for network light activity. Solid = good, sustained blinking = promising.
You asked about other Sling-minded sites, have a look at placeshiftingenthusiasts.com. General discussion, and a number of ex-SlingCommunity folks hang out over there.
Hope things work out...
As AZ has said, the power supplies seem to be a lot of the issues with Slingboxes. I have replaced 2 power supplies on my Slings one for a Pro and one for a Classic. Each time that resolved the issue(s). If you happen to have a ProHd or Catcher as well you can swap the power supplies around and see if that fixes it. The Classic and Pro use a different power supply. $20 bucks to replace the power cord is a lot cheaper than replacing the entire box.
Thanks everyone, I'll give power supply a shot.
My router is fine, I connect it to many different devices.
I really think however I may have screwed an upgrade years ago and forgot, hoping to fix it one day.
Is there a way to unbrick, or I'm just SOL.
You should try a different AC Adapter first before thinking its bricked. As I understand it is not entirely uncommon for malfunctioning AC adapter to cause the symptoms that you've described. On the bottom of the Slingbox, you should see the power requirements; voltage, amps, and polarity. Make sure the AC adapter connected to your Slingbox has the same output sepecifications. Otherwuse, if you have a compatible power supply then you can test it with your Slingbox to see if there's any change.
Otherwise, you'll have to contact Sling Media techincal support for a replacement.