Hello, this is Rip from IMSI/Design, makers of TurboCAD and DoubleCAD.
TurboCAD LE was a free product ("Learning Edition") and was released in 1993... which I believe is Windows 3 era so compatibility with XP may not be perfect. That said I do know users that run this regularly on XP without difficulty so I cannot say for sure what going on here.
Free DoubleCAD XT is a 2D CAD product so if you need 3D, it's not the product for you. (Note, you can view 3D drawings in XT... and, at some point, we will have a 3D plug-in for free XT.)
If you need 3D, though, TurboCAD Deluxe 2D/3D is a steal at $130 -- I am biased, but TurboCAD Deluxe is the best on the market.