I agree, you shouldn't carry on with XP, both W7 and W10 are better but if you want to carry on using Mach3 with parallel ports then you are limited to W7 32 bits, but if you want a better PC and a motion controller then you can also use W10 64 bits. All of the UC motion controllers can be used with Mach3, you don't need UCCNC if it is not working for you.