I recently saw a desktop with a 1.6 Ghz Celeron and was like "Dayyym *****, you old!". Who in their right mind is still trying to play an expansive MMO with a pentium 3 or athlon XP? They both date back to pre 2001 and i can't concive of any reason not to be able to upgrade to at least a processor made in the last 10 years or so.
Buy a cheap netbook, scrounge a pentium 4/ Athlon 64/ pentium d/ Athlon x2 desktop. I could assemble something that could solve this problem from bits off my bedroom floor. I could raid the skip behind a computer rapair shop and find a pentium 4 or better/ equivelant (infact i know someone who did just that...)
I have no doubt the affected players will vehemently and boisterously voice their furious anger in this thread as soon as their carrier pigeons can deliver their posts.