> Your answer indicates all the _SP2_ or _SP1_ etc are not necessary.
half true. that update probably doesn't work for xp sp1 or xp rtm. in this particular case, when you have to restrict the update to not work under sp1 and rtm, you have to enforce XP_SP2_X86,XP_SP3_X86, making the update load only into those serve packs. by other hand, if the update is intended to run under any SP version, then the restrict variable can be set to be XP and X86, that will make the update run under any service pack or version of windows xp (since x86, of course)
by the way, this seems to work as an removal for all the Microsoft Security Essentials:
%PROGRAMFILES%:\Microsoft Security Essentials\setup.exe /s /x
it's also possible do an removal with MsiExec.exe, but i don't advise it under seven. after do that into an seven vm, Microsoft Security Essentials was unable to install again
as for windows defender x86, only this was possible as uninstall:
MsiExec.exe /qn /x{A06275F4-324B-4E85-95E6-87B2CD729401}
as i don't have xp x64, i can't even look at windows registry for an removal, sorry
[]s