Mandriva { was Mandrake } will not run on anything less than a pentium class cpu, that is a choice they made. [ i586 is pentium only ]
if you want to use the 486, red hat's fedora core or debian would be better options.
Being pro-*x and anti-MicroSoft is fine, but there may be a better time and place to wear your "I'd rather die than deal with MS" t-shirt than at a support group for people with multiple sclerosis.