I've had an issue for a long time with Windows failing to boot. Sometimes when I switch the PC on, I get a message saying that a certain file is missing or corrupt. The file effected varies, but is always an important Windows file. I believe I have finally discovered what is causing it - Windows Update. 
I'm quite certain that every time this has happened, it's been after a Windows Update has taken place. Most updates work fine, but most are just Windows Defender updates.
I've Google'd around and found other people having this issue, but coudn't find a solution.
The only thing I can imagine that is causing it is the way I installed Vista. I used an "Upgrade" version to make a clean install, which is possible using a workaround. But many have used that method without issues. And the other people I have discovered who have the same problem didn't use this method. So perhaps it isn't connected at all.
Anyone know of a way I can continue to use Windows Update without making this happen?

I'm quite certain that every time this has happened, it's been after a Windows Update has taken place. Most updates work fine, but most are just Windows Defender updates.
I've Google'd around and found other people having this issue, but coudn't find a solution.
The only thing I can imagine that is causing it is the way I installed Vista. I used an "Upgrade" version to make a clean install, which is possible using a workaround. But many have used that method without issues. And the other people I have discovered who have the same problem didn't use this method. So perhaps it isn't connected at all.
Anyone know of a way I can continue to use Windows Update without making this happen?