MICROSOFT changes the PC files without permission:

According to the researchers, Microsoft Corp. has started updating the files on computers running the Windows XP and Vista, even when users have explicitly disabled the operating systems automatic update feature.

Scott Dunn, an editor at the “Windows Secrets” newsletter, said that Windows Update, the Microsoft update mechanism, has changed nine files in XP and Vista (but not the same files in each operating system) without displaying the usual notification or permission dialog box. The files, said Dunn, are related to the XP and Vista versions of Windows Update (WU) itself.

Dunn identified the changed files on

Vista

wuapi.dll
wuapp.exe
wuauctl.exe
wuaueng.dll
wucltux.dll
wudriver.dll
wups.dll
wups2.dll
wuwebv.dll

And on the operating System

XP SP 2

cdm.dll
wuapi.dll
wuauctl.exe
wuaucpl.cpl
wuaueng.dll
wuctlui.dll
wups.dll
wups2.dll
wuweb.dll