I can't really hear high pitches any more so that might be part of it (actually makes diagnosis hard for some things but different discussion there) but actual coils going crazy or just fans spinning 100% because bad software? What causes the latter probably causes the former as well if it is a thing so you could probably attack it from that front, or do some kind of max resource allocation setup to have it appear as far slower.
Equally if it is an inductor that is whining is this not a matter for some solastic or maybe even hot snot (glue gun glue) to take it out of whatever resonance it finds itself in -- if it does it here then it will probably also do it for modern games when it gets pushed hard?
As far as old games and running on modern windows. I usually take it as a given that I will be ending up on
https://www.wsgf.org/ (originally a site made to get games working on widescreen, today quite a bit more) and probably
https://www.moddb.com/ to have it be nice, anything in line with that then being within normal parameters as far as I am concerned. Every game I have ever owned I used the cracked version of as well as that just seems sensible.
I also have the debate on what I want to go in for -- back when I was... not as old it is not like I was rich and having all the fancy gear. My machines were likely as not to have cyrix and later AMD processors, a sound blaster clone running the finest £10 computer fayre speakers, my CD drive had an error on it that made audio tracks become what I can only describe as high speed modem noise after a few minutes (to this day it means I play heroes of might and magic battles as fast as humanly possible so as to dodge it, this despite that drive being a CD burner as well that died now decades ago), my graphics card (I just about managed to squeak out of onboard) only said voodoo on my wishlist and while I had used a laser mouse that was early enough to need a fancy mouse pad to make it work I still had ball mice at a point when Vista was a nearer than not future thing the magazines were talking about. I would not necessarily go out of my way to emulate any of that but at the same time 486DX100 and all the trimmings using peak of CRT resolutions with voodoo and real genuine soundblaster/creative labs is also not so much a thing me or mine ever really experienced bar the occasional trip to a rich relative which means I might well actually want to operate in the "good enough"/"Just As Good™" regime.
Some of the 16 bit installers don't work on 64 bit windows, though there are usually workarounds.
If it needed an old version of Java (2003 Chrome being about the only thing I would really consider for that), possibly Flash nowadays but eh, old version of visual basic then that can get fun but I usually have vb setup to work for old ROM hacking programs so no great issue from that.
If it is a 3dfx game then Dosbox has not historically done the best at having that mode (and it is usually a notable difference, even if I did not have it back when), today it does a bit better but yeah I would go for wrappers. I don't think anybody would want the S3 virge emulation options of things (those few things that did support it usually doing it out of pity and having far nicer 3dfx modes). A lot of DOS things I will also possibly gravitate to the Amiga versions of just for ease, or 16 bit consoles/PS1 if they have good versions but input can be an issue there (and that is before we consider the things that changed radically -- war games probably being the more prominent example in that discussion)..
midi emulation is its own minefield (
http://macgateway.com/featured-articles/sound-card-history/ for history of sound cards, what one you emulate and means thereof is up to you, I never had anything other than soundblaster and sound blaster clones so your picks might end up different to mind if you need the shiniest options you never had back when) but for the most part that just means what sound font/sound back/instrument library you like best.
All that said I do usually have XP and such machines kicking around. Replace CMOS battery and monitors have VGA inputs for a reason, granted I have DVI outputs for a lot of those as well.
Can't say I have ever been bothered by the Harry Potter games -- seeing prices in a game shop for the GC version the other day though and some noting the magic system has me marginally curious though. For these purposes I would however want to investigate what is causing the issue.
JM 
