What is the old processor Make & Model that does work? Also Motherboard Make & Model?
With the 5600G installed, restart your PC 3 times when it reaches the Windows logo. The 3rd time you restart your PC you should automatically enter Windows Troubleshooting menu.
Click on Startup problems and see if that helps or not.
If not then from there see if you can restart your PC in safe mode with Networking or not. If you can't enter Windows Safe Mode then remove all the RAM from your Motherboard except for one Ram stick and see if it boots into Windows.
Possibly the Ram you have installed may not be compatible with the new Processor but compatible with the old processor. Sometimes using one Ram Stick help to make it more compatible.
Appauls give some very good tips on how to fix your error: https://appuals.com/driver-pnp-watchdog/
But the above article is only good if you able to enter Windows.
Personally since your PC works normally with the old Processor and not the new processor it could be due to incompatible hardware or even Windows OS.
From everything I have read on your error installing Windows OS again will be the last resort. Since you have a new Processor and you don't have any incompatible hardware then I would install Windows again.
Installing Windows again is something I extremely rarely suggest. Mostly, I suggest doing a Windows In-Place Repair which is running your Windows Installation setup while in Windows Desktop. Either from Microsoft Windows Download page or from a DVD or Flash drive with Windows burnt on it.
