How Windows Know?!

[xtremee]

Hi everybody,

i wanna to know how i can remove any previous version of Microsoft application and setup the old one?

→ If u have WMP 10 and u wanna to remove it (i know that WMP 10 is the best ,but it is for example only) and setup WMP 9 windows don't let u make this.

→ If u have Windows xp Pro_sp2 if u going to run Windows xp (without sp2) windows don't let u make this.

→ If u going to run Windows 9x in Windows NT or later Windows Don't let u make this.

→ If u setup IE 7 and u wanna to get IE 6 windows don't let u make this.

→ If u use MSN Messenger and the new one have been released Windows don't let u run ur old one ( i think this from the pprogram it self ).

I think that is sysoc.inf have some responsiblity for this (i.e. u can show wat is hiden then u can remove the new and setup the old one)

So, How Windows know the new one?

Regards,

Xtremee