you can get refurbished PC's that have XP on them with very good specs for £30 off of ebay, the sellers where really good as well as they replace any that have a fault within 60 days (they service every pc before selling) even so with your currant pc you say "it is near its end of its life" in what respect it could be a simple fix such as cleaning out all the dust inside the case to allow the fans to work better.