Windows 10 - 'explorer.exe class not registered' & ms-settings missing

Hello everyone! As every other W10 user, I constantly run into some problems. On sunday my computer was working perfectly fine and today when I turned it on, everything started acting up (note that this is not the first time, seeing as I already reinstalled w10 already 3 times in the past month). Where do I even begin with what was bothering it. First things first, computer was SUPER slow - like, slower-than-snail slow - and this didn't surprise that much considering the fact that I have windows installed on HDD (I was kinda low on budget for SSD, but I do plan on buying it) but it still didn't serve as an excuse to being so ridiculously and awfully slow. Then next thing is that whatever program that I want to start just ends up being big white window with 'no responding' message. I start a task manager but same thing is with it. I went and downloaded CCleaner and Malwarebytes thinking they would help and they did. Sort of. Turned out that computer had 2 trojans (which would explain his painful slowness) and after MB deleted trojan, another problem came up. I rebooted windows and everything was fine until it loaded desktop. Then when I tried to click start meni button, search or windows store - it wouldn't budge opening. Neither left click nor right click work. Right click works only for taskbar and will only open options menu for taskbar. Also, I spent approx. 5 hours trying to fix the next error that came up when I clicked on win store ('explorer.exe - Class not registred'). I found billions of fixes but none of them worked but instead helped me out finding yet ANOTHER problem. Ms-settings: doesn't even exsist on my computer anymore. And for windows it says that 'they're not activated' which is a total lie because they are. So what is going on here? I mean, yeah I had problems with W10 but never this major. I'm tired and pretty sure I'm straight up loosing my mind because I tried sfc /scannow (that resulted in yet another error), wsreset.exe does nothing, tried booting in safe mode - no changes, returning to previous builds - no builds available, any kind of recovery - no recoveries available and resetting PC is not an option because it says that 'reset couldn't be done on my PC & no changes were made'. I know that I could easily just download iso file from internet and install W10 from scratch but I have papers due and that would cost me a lot of time. Also I have a lot of things on computer - too little space on USB. Any help here?

UPDATE: cabinet.dll missing error pops up quite frequently too

Hi and welcome to the forum. Please could you paragraph-ise your question to make it easier for us to read.

Did you run sfc in command prompt as administrator (that part is important).

My question was though, did you run cmd prompt as administrator.

Hello, given your situation I would
a. back up all your data from desktop to favourites and any other files
b. attempt an in-place upgrade repair install which will keep all your programs and most settings (not language settings e.g.)
Repair Install Windows 10 with an In-place Upgrade - Windows 10 Forums

This will take as long as installing Win 10. It does require the appropriate Win 10 iso/DVD/USB device.

If that doesn't work, then you could use e.g. Laplink PCMover (not free!) with a disk image of your current configuration to automatically reinstall most programs and settings after clean installing Windows.

Noted 'Too little space on USB' - implies you may not have full backups and no spare storage.

If you can't use your existing Windows even to back up files, then use a live boot disk to boot your PC (e.g. the one available at the top of Software and Apps in this forum), connect e.g. an external USB disk, and back up that way.

For the future: use disk imaging updated periodically, before a major change and afterwards, so you both have a complete backup and can restore your PC to a previously working state quickly and without tech support, hardware faults aside.