It looks like your settings for Temp and Temporary Files match so from a Blender point of view it ought to work I think.
Do you have any fancy security/anti-virus software installed? In some cases I’ve seen Windows get weird about allowing Blender to write to arbitrary locations on the system, possibly based on whether you’re an ordinary user vs. administrator, 3rd party security software, or in highly managed corporate environments. Some times it makes a difference where/how Blender is installed (zip installer extracted somewhere random vs. the MSI installer putting the files in an official location on the machine that is more trusted than code that’s trying to run from wherever).
One way to test the copy/paste stuff is to see if each version can copy/paste to itself across a restart. This might clearly confirm the behavior you describe where your 2.79 can’t paste to itself. So start one of your Blender versions, Create a Torus or whatever, select and “copy” it. Then exit that Blender and restart it (the same version), and now try to do a “paste” and see if it works. Then try the same series of operations with the other program (use a different object type so you can tell where it’s coming from if the paste works).
I believe the copy/paste works by storing the copied data in a permanent file in the temp directory, so the above test will tell you whether each version is being able to successfully write to this file and then later open and read it. If it works with one and fails with the other, then you’ve narrowed the problem down and just need to focus on why that version is failing. If it works with both then it must be some other issue.