Surprized ? I am. I still own a computer with xp pro & don't have a problem with Civ 4 BTS. I also have a newer computer with vista home prem .no problems. A friend of mine installed Civ 4 ,warlords & works fine. went out & bought Civ 4 BTS, installed, but would not play. asked for original disk. tried to change compatebility in game exe , came up error . If anyone has experienced this &/or knows a sollution please post..