Using Windows 10. I'm not paranoid about SideFX selling my data or anything like that, but I'm a real control freak when it comes to technology and I like having absolute dominion over everything on my machines. I already get super itchy whenever I see something like three Cortana processes running on my Task Manager, so is there a way to stop things like “hserver” from running while I'm not using Houdini?

Windows?

this is maybe your friend, switch services from automatic to manual…

google for it…
or type it directly in the search window..

but you do not really want to change this from automatic to manual ;-)

I'm not as tech savvy as I'd like to think, what exactly does disabling services.msc do?

services.msc is simply listing all services and the start options.
It'll not harm at all if you type this in the “search” input and press enter.

Then a big list with all “services” will pop up in a new window.
(see image)

There you can change the start up options for every service
and stop this, too.
But in a “normal” environment there is no need to change there something :-)
Sometimes it can happen, that a service which was started automatically
blocks another service which is started “manually”.

Conclusion: there you'll find “hserver”,too
Your question was:
“….so is there a way to stop things like “hserver” from running while I'm not using Houdini? ”

Yes, you can, but… I'm sure you do not want this…
If you disable automatic start, maybe you have to start it manually
no, please let it at it's default.

If you need to know, who is calling “home” you need to go deeper.

http://www.sidefx.com/docs/houdini/nodes/out/hq_render.html [www.sidefx.com]
http://www.sidefx.com/docs/houdini/nodes/out/hq_sim.html [www.sidefx.com]

look for: HQueue server

to see what it is good for.
Forgotten to say:
Whenever you change defaults, and then run into trouble,
do not forget to say it if you contact support :-)

You have alright English, I could understand you just fine
I didn't understand one thing though, how does disabling hserver's automatic run affect using the actual program?

I'm not sure if it will.
But I won't try it :-)