My Manjaro system is lagging

Hello, till yesterday, my laptop was working fine. But today I booted and it’s lagging. Windows, browsers, icons, files all are taking a lot of time to load. When I boot Manjaro, the booting is fine till I get login page. But when I log into my user account, it all becomes so slow. It’s taking me more than 2 minutes to load the whole desktop. I re-started Cinnamon and even restored Cinnamon to its default settings but stilll no luck. What could be the issue? Also, my CPU usage is fluctuating from 0% to 25% to 50% and sometimes even 100% but I’m unable to find any processes which are using CPU this much. Even running commands in terminal are taking seconds to load and give output. Also, my laptop sound isn’t working since today. I don’t see any audio devices in settings.
My laptop is dual-booted with Windows10. I booted Windows 10 today to see if problem is there as well but it was working flawless so it doesn’t seem to be a hardware issue to me.

Your post does not provide much helpful information, so please start posting at least output of:

inxi -Fza

Maybe you are running out of disk space?

Also make sure Windoze is fully shut down before switching to Manjaro, fast startup etc. should be disabled in Windoze.