To my surprise there are still people out there who thinks that you need WindowsXP to play Dungeon Siege these days.
This is simply not true. Over the past years I have installed it on Windows 7, 8.x and Windows 10 and all of them were 64 Bit versions.
You don’t even have to tweak the compatibility settings. All you need is to install DirectX 9.0c (from June 2010) and choose the correct setting with DSVideoConfig.exe
I made a video on how: