Windows 10: CPU 100% out of no where

Hellothank you for taking the time to read thisOut of nowhere 2 or 3 days ago my CPU have been working on a 100%. i tried different solutions it didnt work.so i reinstalled windows keeping personal files and still having the same issue.Then i reinstalled windows again with a clean installation and deleting everything. and the same issue still there!i tried to upload screenshots it dont let me.Mostly its "Task Manager" taking 80% idle with no other apps running. and if i ran something like a game it takes the most and Task Manager goes back to 1%.my CPU temp on idle is 67C with the pump fan run

:)

 

100% Cpu

• #1

Cpu: i5-8600

GPU: RX 580 Series

RAM: 16.0 GB

Motherboard: Aorus

Power supply: Corsair Vengeance LPX 16GB DDR4

Resolution: 2560 x 1080

Was working fine not it just crashes my game the game is Tom Clancys Rainbow six siege but I can barely also start up other games

 

CPU constantly at 100% in task manager

That is exactly what I did previously. I tried setting max to 80% to test and task managers cpu displays constant 80% instead of 100% on the performance tab and 80% above the cpu column in the users tab. Sadly it has no effect but thank you for the suggestion.

 

[FS][US] CPU, NForce4 skt 754 motherboard (with PCI-express slot, rare!), DDR RAM

bump, CPU's stepping is now listed.