viveleroi0: you need to explain that to your wife, then, that you need it for class. If you explain that the small investment now will last for a good 5 years, and that hte other computer will still be useable, for the child, and for her? maybe she'll be more open. or sell the old box off for some money for parts
(the bits of it you aren't recycling).
Good luck, I know how hard it is ot have an aging system