[adrian_b]

Windows 95 was not Windows NT and it still used the FAT32 file system, where it was not really possible to enforce access rights.

As TFA says:

You even had installers that took even more extreme measures and said, “Okay, fine, I can’t overwrite the file, so I’m going to reboot the system and then overwrite the file from a batch file, see if you can stop me.”

[TheAmazingRace]

Well and the earliest versions of Windows 95 used FAT16 (specifically VFAT for support for LFNs or long file names). So enjoy those ridiculous cluster sizes if your hard disk even approached a gig or so.

[nikau]

That's because windows locks the file name vs inode like Unix, so was really the only way to update any file in use like libraries.