So, first off my laptop disconnected itself at 11:45am this morning and I cannot reestablish contact with my router.

Then I got out my Dads Dell laptop which has been in a bag since January, and has not even been turned on since 1/2/16.

It too is unable to communicate via WiFi.
In both cases I get the same message: WiFi does not have a valid IP configuration.

How is this possible?
They cannot both have broken WiFi cards. They cannot both have a virus since mine was working fine until 11:45 this morning and Dads, before it went into storage, was running fine and had not been used in a month.

Its not the router as I am posting this on it using my Moms Lenovo laptop that is on Windows 10. Only the two machines on 8.1 are malfunctioning.

I have tried uninstalling and reinstalling the network adaptor driver in both machines. I manually reset the IP number through the command window in both machines.  I reset the IP/TCP stacks in both machines. In my machine I restored windows back 24 hours.
It does not help.
I have also tried to connect to the router using the ethernet port on my machine. Once plugged in it says it cannot find router. When I run the diagnostic it then says the ethernet port now does not have a valid IP configuration.

What is going on? What erased my IP configurations? Why cant I reset them. How can a system that was in storage for a month have the same problem as a system that was worked daily until this morning?

This is a complete shot in the dark, but I had a case that was superficially similar.

It turns out an update on one of my AP's added a default setting for an IPv6 guest network.  Not all of my devices were set up for IPv6, so they couldn't connect at all.  The ones that could connect were on a very different IP range ( 45.x.y.z instead of 192.168.1.x , as I recall ) and couldn't see some of the other devices that were connecting on the IPv4 from the other AP.  

Basically I had three groups of devices:  IPv4 and working, IPv6 and isolated with no internet, and no connection at all.

I have a lot of devices, but I'm not quite near filling up IPv4 yet so I disabled the IPv6 guest network for now.   Doing that, followed by a round of reconnections, had me back up and running 100%.

I didn't get to try your fix yet, when for some reason my wifi just started working. I have thrown a half dozen fixes at it without working. I am not sure what did work. The last thing I tried did not work on restart. But then I stopped to watch the car chase on Bullet on TCM and when I came back I suddenly had signal.

The internet is full of complaints and supposed fixes for this. It seems to be a common bug with Windows 8/8.1.  And there does not seem to be one guaranteed fix.

The last thing I tried was from this page http://www.kapilarya.com/limited-wifi-problem-in-windows-8

But even this on restart didn't work.  But after walking away a few minutes and coming back, it was on.
Now I have to check if I can get my Dads laptop to work now.

I telepathically threatened it with my dick.  Should be fine now.