Yes, its instores to buy; A Windows Live game.
yes you do, but there are hacks to make it work on XP
halo 2
not legally
You can install SP2 from the windows update area. Check optional updates if it isn't there
try install windows xp service pack 2 then install the sims 3 but there might be a chance it will erase the data of the old windows xp if all sorry if this doesn't work.
Only for Windows Vista, but you can use it on Windows XP, but that will stop Multiplayer from working.
XP Home Sevice PK
http://www.softwarepatch.com/windows/xpsp2.html go here and download the patch, then install. easy as that
This is kind of a two-part answer, because I'm not sure about the question. 1 - Halo (the original) will work on XP, and should work on Vista. 2 - Halo 2 will only work on Vista.
You can install Windows XP Service Pack 2 with the link below. http://www.soft32.com/download/63-58736/WindowsXP-KB835935-SP2-ENU.exe
Yes.
Yes. However, you must make sure that the version of Halo 2 you are trying to play is the PC edition rather than the XBOX version. It should read "Halo 2 for Vista" or something similar. Now this does NOT mean it is only compatible with Vista. Halo 2 is compatible with Windows Vista and Windows 7, but not Windows XP.