I meant, there is nothing "broken" about XP, still the 2nd most popular OS after Win7 and widely supported. No reason to 'learn anything new'. If she needs a replacement machine, I'd recommend a refurb from a local electronics store. Our local Microcenter routinely has refurbed Dells and HPs for around $140 (Core2Duo, Win7 machines) or $80 (for P4 XP machines). There is nothing "new" to learn about Win 7.
Win 8 with Start8 is almost useable if the machine has to be 'new-new'.