Hi, I'm Bernard, a fellow Windows user. I'm happy to help!
Since the PC is constantly restarting, I recommend doing a system restore. Kindly follow the steps below:
Before doing the steps, make sure to remove all peripherals connected to your PC and just retain the Mouse, Keyboard, and Power source.
First, we need to go to Windows recovery mode and try the options there:
Restart the device 3-5 times until you reach Windows recovery mode, wherein you have the option to select Continue, Troubleshoot, or Exit.
Or try to press and hold the Shift key while continuously pressing F8 while starting the PC
Then on Windows Recovery:
Do System Restore:
Click Troubleshoot> Advanced options> System restore - Follow the prompt and choose the date when it was working fine.