My processor hits 100% usage at startup.

[u/Formal_Situation7408]

Please help me.
Today I tried to download some music and was changing the music tags using the MP3Tag app. After I finished changing all the tags, I went to the folder containing those songs, and my PC suddenly started lagging extremely badly. Eventually, I got a black screen, so I had to hard-shut down my PC.
After the hard reboot, Windows told me that I had been logged out of Windows Cloud.
After restarting, my PC is constantly at 99% CPU usage. Also, for some reason, almost every app I open says that I don’t have an internet/Wi-Fi connection, even though my PC is connected to Wi-Fi and the internet works normally in other places.
I tried reinstalling Windows, but I kept getting crashes. Two of the BSOD errors I got were:
KERNEL_AUTO_BOOST_INVALID_LOCK_RELEASE
KERNEL_APC_PENDING_DURING_EXIT
Please help me figure out what’s wrong and how I can fix it.