OK, here goes:
1. There is just the single letter C: in File Explorer, so only I guess only one drive.
2. The properties say it's a Western Digital WD10EZEX-75WN4A1 - 1TB 7.2K RPM.
3. So it does appear to be 1 TB, but the 7200 rpm means it is mechanical and not solid state, am I right about that?
Is that alone the reason this thing is so slow, is that some antiquated feature? (But my 10-year-old cheap-ass ASUS laptop I use for my business must have much older components, and it's plenty fast without any of the problems of the desktop).
Yes, you are right about that.
As far as we know, it is functioning properly.
Normally, from a completely off state, I'd expect a PC like yours to have Windows fully loaded and ready to go within a minute or two.
If the drive were instead an SSD, that might be reduced to 30 seconds.
You don't seem to be doing anything with the PC that is strenuous or requires much CPU power.
For most operations, you'd never notice the difference between your 7200 rpm drive and an SSD. It would be noticeable on stuff like starting up, virus scans, copying a huge bunch of MP3s, opening a big application like Photoshop, backing up 100,000 files, etc.
But not for standard stuff like looking at this forum, creating a folder, or watching Youtube.
No doubt Dell installs a bunch of stuff you don't need and will never use by default. That might contribute. Some of that stuff may run every time you start up....unnecessarily.
You may have some drive fragmentation, but that is rarely a severe problem. It is fixable.
Normally, we'd probably tell you to do a clean Windows install, but you don't know how and it's too much to realistically expect of you.
I'd take it to Micro Center, but first I'd decide on a general plan:
1; is budget a concern? Will you spend 50, 250, or 500?
2; in all likelihood, a clean install would help and Micro Center can do that. Guessing 150 or 200 for that alone, re-using the existing drive?? Total guess.
3; new SSD and keep the existing 7200 drive also is possible; that might cost an additional 150 or 200.
Might be 400 or 500 total. Do you balk at that?
At a bare minimum, I'd add an SSD and get a clean install without all the Dell crap.
I'd back up all my personal files before taking it to Micro Center.
Another possibility is to continue this or another thread and try to walk you through fixing it yourself. From your comments, that is a NON-STARTER and understandably so. I tend to agree with you, given your reluctance.