"Chaos Gate" is a round based 40k strategy game. Was released around '99 and looks a little dusty. But its so awesome, im playing it again atm. You are controlling a bunch of Ultramines, fighting against the forces of a Chaos Lord. Has a very good story, nice videos and awesome voice overs.
Problem is: it wont run under Windows XP / Vista.
Even if you get it to run in compatibility mode, you will experience tons of bugs.
For Windows 2k I can give you a workaround, editing the registry.
For Win XP/Vista you need "Virtual PC 2007 SP1" (freeware from Microsoft) and a copy of Windows 98SE for creating a virtual machine.
Easy to set up and runs very stable.
And dont waste your time getting it to run stable under XP / Vista, I spent days on that, there is no fix...