Unable to Access Windows Installation Service

Recently I found that the MSI installation files on my computer are useless. So:

1. Check whether Windows install is stopped in the "service". The result shows that the service is gone.

2. You can go to system32to check whether the msiexec.exe file is absent. It turns out that the file is missing. This world! I copied one from another machine and found that some MSI files are available, but some are still unavailable. Why?

3. The problem lies in the service. We need to register and start the Windows install service:

C:/Windows/system32> msiexec.exe/regserver

Okay, you can use it.

I want to know when my msiexec.exe file will be missing. Is it poisoned ?!!