I will not state categorically that this fix will work, but it has worked for me so far.
I believe the problem lies with Win 8.1's bizarre power management of the wireless adapter. One or two posts have alluded to this already, and it's worth attempting.
Hold the Windows key and hit X.
Click on Power Options.
Whatever power save scheme is selected, click on Change Plan Settings.
Click on Change Advanced Power Settings.
Click the + on Wireless Adapter Settings.
Click the + on Power Saving Mode.
Click on each condition available (plugged in or battery in the case of a laptop) and select Maximum Performance.
Click on Apply, and exit the whole area.
It might be that this works only on my HP laptop, I don't know. But it worked like a charm for me.
My theory: Win 8.1 introduced some screwed up new power management scheme for the adapter. I have read complaints that distance seems to make the problem worse, and I found that myself. Also, being on battery power seems to make it worse. My theory is
that the power management software looks for signal strength, and, if you are, for example, sitting on your deck on a breezy day, whenever there is a drop in signal strength, it just shuts off the adapter. This lines up with facts: on battery power, the
adapter is already getting slightly less juice, and sitting far away from the access point makes the signal strength highly variable.
If I may rant for a few sentences, I also am angry with Microsoft, who either know about this and haven't fixed it, or don't use their own product. But I want to add that I am SICK TO DEATH of these multi-billion dollar corporations blaming each other for
our problems. Every one of these incompetent weasels tries to tell us that it's the other guy's fault. They are supposed to work together, are they not? No wonder people love Apple-- one company holding all the software and hardware developers for ransom,
but making sure it all works.