dual boot *linux* & lost passwd

I wana have both redhat 7.2 and 9.0 on my machine, i.e I want to have two versions(7.2 and 9.0) of rhl, on the same machine, any1 any idea ?
i(root) forget my password, any wayz to recover the lost passwrd… i m root of my 9.0 linux box.
third, do u heared abt the “tarbal”, if so, then share ur knowlge with me….. u guess right i m a newbie

Regards,
ibnerazi