Everything is too small -- windows 8.1 not allow me to enlarge entire interface?

That is indeed an interesting observation.  In that case, can I ask you to try both of the remote desktop programs inside Windows 8.1?  Perhaps the problem lies only with one of them.  I'm assuming that if you used the original Windows 7 remote desktop program (which is included in Windows 8.1 but hidden), it might work better for you.

1. To try it, run the command MSTSC and use that as your remote desktop and observe how it functions. That command is from back in 1994 before "remote desktop" got it's new name. Back then it was called "Microsoft Terminal Services Client"
2. Then try again, but using the modern "remote desktop" app from the app store here and see how it functions.

I'm curious to know the results and if one of them works better than the other.

It was written for other reasons, but my blog post here (and the links provided inside it) give a great overview of what DPI is, how it works, and how to tame it to your liking.

I have Yoga 3 Pro, purchased about a year ago, and I have the same problem.  Windows clearly has not corrected the problem.  Using QuickBooks or my PDF converter program are agonizing (in desktop mode, which is where they reside).  Even with my glasses, I have to lean into the laptop to see the menus.  Even worse, I dialed into an online class and the chat room text was so small I was forced to use the magnifier to read the posts from class participants.  I tried all of the scaling and resolution options in the settings, but the menus and icons remain tiny, even if all other text enlarges.  I love my Yoga for lots of other reasons so I'm just putting up with it for now.  Here is a good article about this problem.  It refers to the Yoga 2, but applies to Yoga 3 as well.  At least I know I'm not the only one.

http://arstechnica.com/gadgets/2014/03/lenovo-yoga-2-pro-review-you-say-you-want-resolution/2/

Hey Mad_01,

I've had this as well, wrote about it at length and discuss some other options you can use here. It's not perfect (it still irks me just about daily), but it's not something that has a better solution than that really concludes there.  The problem is the only real solution is to just take the image the program is outputting and have the OS zoom it (just like it does for multi-display DPI adjustments would be fine), but even in those low thresholds (usually no more than 50% increase), you get severe blurring.  The trouble is the program is specifically sending a picture of x by y size pixels, but that's incredibly tiny on a "retina" level screen with so many pixels. To prevent the blur, the application can be built to use vector graphics and text/layouts that can adapt and scale correctly, but the application developer has to make that choice.

Now really it might help if they just employed the same DPI scaling used for multi-mon but let you intentionally enlarge a single app (just willing to put up with it getting more blurry and pixilated).  Apple had to do that when they first got retina iPad, the old "2x" button to double the app size but make it slightly blurry. Although in Windows the average increase from an app that used to expect 1024x768, is really going to need to be enlarged 4x or more, so the blur could be severe.

Eventually, as with Apple, most programs will get updated for the new screensize when their programmers release updates.

Thanks for sharing your post. This was a perfect way to convey this issue. Its good to know that I am not the only one whom is having this problem. And the Windows 10 upgrade I had to revert back to windows 8.1 of which I do not remember having these problems prior to Microsofts suggestion to "upgrade to Windows 10.