System interrupts load the processor at 100%, how to fix it?

Question

Windows

There is an HP4540s laptop with specifications (working):
- SSD ;
- percent. i5-3230M ;
- RAM about 8GB .
Initially, they gave away a laptop with the problem that it was working slowly, found the reason - percent. I loaded 100% of the Trojan, I didn’t remember the name, no matter how funny it sounded, I found this infection, neutralized everything, it works better.
Most importantly , I decided to use it in my work, a day later I received a more or less working device, but something felt wrong and wrong. You start using any browser or some application, and as soon as you open the disp. tasks, you see a process called " System interrupts ", which loads at 100%, but after 1-2 seconds it drops to 0.4-0.7% and under observation, it doesn’t rise anymore, I already thought that maybe this is happening, because disp. tasks opens and therefore loads the percent, as if this is the norm, but in the future there are jumps up to 30-40%, this happens once a minute or two. Also, the browser or other software behaves strangely, like Skype, etc., when you start and wait, the system is also 100% loaded, while other applications work or do not work, it does not matter.
Please, I'm waiting for reasonable recommendations, maybe someone came across, if some information is needed, I will definitely add or answer in the comments ?!
PS there are solutions to this on the world wide web, they say it's all drivers, etc., go to the device manager, check there, disable it, but this is not an option, disabling running device drivers, in my opinion, is not advisable and not normal.

Answer 1

1) Finally rearrange the window to clean.
After any virus invasion, the computer and all drives connected to it are considered compromised and must be cleaned up by formatting cleanly. After that, you can roll the OS and data from backups.

Answer 2

In 99% of cases, it is impossible to fully cure a PC after infection, something will definitely remain damaged. Try formatting the disk and installing a new Windows.
The laptop is also old, so it makes sense to disable protection against Spectrum and Meltdown with the InSpectre program. On older computers, this protection noticeably affects the I / O of all devices, including disk and network.

Answer 3

I support Bobby Slate 's suggestion to reinstall the OS cleanly from the correct image. That's even just not to think!
And then I suggest not to get paranoid and not get hung up on these percentages. The car is far from new. They removed one bottleneck - they installed ssd, another appeared - the processor. Works as best it can.