Pain, Frustration, Insanity.
Yes, this is about Windows. A very specific problem (Is there any other kind of fact about windows?), caused by the removal of DOS from WindowsME onwards.
I'll start at the beginning, Wininet.dll is a Windows networking system file created by Microsoft. It is not present on some clean installations of Windows 95 and NT, but it is present even on these machines after installing Internet Explorer or one of many other programs.
This is, great and all, but should your copy get corrupted (Not impossible, my case in point) there is little you can do about it short of format, reinstall.
See, back when you had DOS, all you had to do was exit windows, and copy a backup version over the dll that was causing you grief. This will not work now. Even in 'safe mode' this dll is in use all the time.
I have been told by Windows support
"Rename the file and then replace it"
I have been told by WindowsME:
"Cannot rename WININET: The specified file is being used by Windows."
Which leaves me banging my head on the desk and installing linux.