AC-66U broke

[micksh]

It was working fine, but then my wife disconnected it. When I connected it back, internet connection disappeared. Router web page showed WAN disconnected (of course, it was connected and cable modem worked fine).
I could not go to some setting pages - router's web page wouldn't open the pages.

Then I did factory reset (held WPS button for 30 seconds). Now I can't configure router. I can login with default password and see first router page, but then it doesn't open configuration wizard.

The weirdest thing - when router web page is active my browser (latest stable Firefox, Win 8.1) opens go.microsoft.com web page every few seconds - I can have 20 tabs with go.microsoft.com in a few minutes.

I disconnected all my wired network so it was only PC, router and modem.

After all I took some old Cisco router and put it in place of Asus. Then everything worked, so it's not my PC or network.
The firmware on AC-66U was latest official from about a year ago (can't chek it now) and it's been working fine for a year. Now warranty ended.

Any idea what it might be and how to fix it?
Thanks.

 

[TonyH]

Hi,
Did you power cycled router, modem, PC? Cleared browser cache? Tried different
browser? Could you reflash router f/w?

 

[micksh]

It's weird. Yesterday I tried everything you said (except clearing browser cache but I tried two browsers). Nothing worked, it would not show configuration web pages.
Then the router was standing for whole day, then I turned it on and did a factory reset again (with reset button long-press).

Now everything seems to work and I can configure it. Thanks.