A new development has arisen in the continuing saga of my attempts to find and cure the problems with my computer. I found out yesterday that the problems are NOT caused by a hardware fault.

For months I've been under the distinct impression that the situation with Explorer.exe randomly crashing and having to restart, as well as Windows randomly refusing to acknowledge the mere existence of fully functional USB 3.0 ports on my motherboard, were being caused by faulty hardware. Turns out, however, that the problems are now also occurring in my laptop, which up until yesterday never had this issue. I was downloading a fresh copy of Windows 7 using qBittorrent and a VPN service, and after I got done downloading and getting the media ready to install the OS to the desktop, and was in the process of shutting down my computer, Explorer.exe stopped working and had to be restarted.

Up until yesterday, I had not installed either the VPN client or QBittorrent onto the laptop, so that means that the most likely explanation is that one of these two pieces of software conflicts with other software on the computer. After doing some online reading this afternoon I found that several AV programs, such as Malwarebytes Anti-Malware, conflict with the VPN client I'm using. I haven't been using Malwarebytes (or MBAM for short) on the desktop lately as it's being persnickity about updating and I can't stand to use the newer UI that they've added since the program was bought by a major corporation, and so I've changed it on the desktop. But the laptop still has MBAM on it, so there could be a real thing there.

Of course, the desktop has also crashed without MBAM (I replaced it with SUPERAntiSpyware), and there are other software possibilities I've been trying to find documentation on because of suspicious behavior, not the least of which is VirtualCloneDrive, since I seem to have had more problems with that installed than I have without.

So anyway...

TL;DR: the Explorer.exe crash wasn't a hardware problem but rather a software problem, most likely a conflict involving my VPN client and another program.