I found a way to solve the problem.
Windows 10 KB5000802 Security Update is the culprit and it needs to be uninstalled. Then mathematica can work normally.
But there is a problem, Win10 will automatically update which is very annoying, because it will install KB5000802 Security Update again and Blue Screen will happen again. So you should disable automatic updates in Win10, then mathematica will work again, but that means your computer will never have a security update, So you have to make a trade-off.
One thing needs to be mentioned more, I found out that my colleague’s computer also has version 12.1 installed, also has Win10 KB5000802 Security Update installed, but his compouter can run mathematica normally. And my computer is not even if the computer system is reinstalled. This is a metaphysical thing and I don’t know why.
Operations for uninstalling security updates and disabling system updates are readily available online, you can find them everywhere. Hope the above description can help those who encounter this problem.
KB5000802 is also a culprit for the failure of some printers to print, that’s the problem I had before, if you hit the print button and the printer didn’t respond, this could be the reason.