You're right; it is a real gem of a machine. The Taig DSLS 3000 uses Mach3 as its CNC controller program, and it comes with a Mach3 license. Mach3 runs fine on Windows 7. The reason so many people use XP is that it's the version that's usually on the older computers that have parallel ports, which are usually used to run the Taig. But if your Windows 7 machine has a parallel port that can run in EPP mode, then you should be fine. If not, you can get a converter like the UC 100 to run it off your USB port, or something like the Smoothstepper that would run it on ethernet. However, that "dusty" (blow out the dust first) XP machine might actually be your best choice, since you could wipe out anything that conflicts with Mach3 and dedicate it to running the Taig . You might not want to do that to your Windows 7 box.

I'm sure it's possible to run the Taig with LinuxCNC, but it would take some figuring out, especially since the DSLS 3000 relies on the limit switch function of Mach3 to trigger the shutoff when the servo band is exceeded. LinuxCNC has a limit switch function, but you'd have to make sure it's called up when the error occurred. And if you were running LinuxCNC, you'd be on your own for tech support, since I doubt the folks at Taig would be familiar enough with it to offer much help.

It's great that you're learning to speak "G", but I think you'll eventually realize that it's a lot more time-efficient to use a CAM program to go from your drawings and (especially) 3D models and the CNC control program of your choice.