I could go on a rampage talking about the differences between win and linux, but i do not see it appropriate, let me just say that after spending over 30 years with computers (professionally for the last 20 some years), i really regret wasting my life with windows. Linux just works, however you look at it. The absolutely astonishing feature of Linux it that i can install it on anything (hdd, ssd, usb even my Galaxy note 3) and connect it to any computer or laptop i have (over 20 of them) press the power button and have the system running in 10 to 20 seconds, with everything already set up and running, no drivers no installations of any kind etc.
Oh and did i mention, NO viruses, none, nada, .....
As for hardware, find Dell optiplex computers with pentium 4 or pentium D, even core2duo work like a charm, and they cost next to nothing, all have a parallel port and more can be added. They have a low latency and are very reliable. Am using a pentium D 2.8 GHz version for over 4 years, it never flinched.
Regards,
Tom