Sadly doesn't look like SWAT 3 runs on modern systems, compatibility modes for XP and 9x don't help nore does dandy tricks emulating an old GPU in software ala dgVoodoo. Although I suppose, loading Win98SE into a virtual machine might work.
That's a great shame because the game was both pretty well done and ahead of its time nearly ~20 years ago. It remains the best tactical shooter I've ever played, and that's probably been a lot over the years.
On the flipside with a little lovin' the original R6 runs pretty well. The only technical issue I've had is a ghosting between the mouse cursor in and out of game which makes using the menus a hard on the eyes. Rather than taking my chances: I stuffed dgVoodoo's Direct3D libraries in to begin with. R6 is so old it still offered a software renderer, so might not be so necessary.
I remember first playing Rainbow Six and finding it both intently interesting and quite frustrating as a kid; mainly for the laser-eyed snapshot of death effect, which is not as big a problem decades later. What remains irksome though is that path finding was effectively infantile back then. Thus in a game that resolved to plan a strike with multiple fire teams -- you've got an A.I. that can barely avoid walking into walls just trying to follow you around. Aside from that, I'd say it remains a good game.