When you cannot trust your OS

On linux, when you are not doing updates, files in /bin, /usr/bin, /sbin, /usr/sbin, /lib, /usr/lib, /lib64, /usr/lib64 are never written, so they cannot get corrupted unless there is hardware or file system failure.

On Windows XP, people take mysterious behavior rather well. spoolsv.exe suddenly taking 98% CPU? No problem, since you don't have a real job, you can just reinstall all your printers. But you might also want to

C:\> sfc /scannow
and "wait while Windows verifies that all protected Windows files are intact and in their original versions".

I haven't installed anything on my PC for decades and haven't updated anything for years, and my hard disk SMART checks look great, so I have no idea why "protected Windows files" will spontaneously decay, but what the heck, just run the damn command.