Good day! I apologize that you are having this issue and I am hoping we can work through it and fix it.
For some troubleshooting, boot the PC into safe mode. Does the CPU remain at 43%?
Safe mode: https://support.microsoft.com/en-us/help/12376/...
If not, clean boot the PC:
Clean boot: https://support.microsoft.com/en-us/help/929135...
If it is still stuck at 43% then you want to go into details of the cpu processes in task manager. Sort by highest usage and turn that program/service off.
Also you may try a repair install to fix the issue.
Start your PC then just as Windows loads - press and hold Power Button for 5 - 10 seconds to perform a shut down. Do it 3 times. You may only need to do it twice, but on the third start Windows will boot into the recovery environment.
You can also hold shift > press restart in the start menu to do the same
1:
Go to Troubleshoot > Advanced Option > Startup Repair
This will try to make Windows repair itself.