This if for my customer. I fix PCs for a living.
(1) Can I boot a 64 bit Vista Home Premium OS PC from a 32-bit Vista Home Premium Install CD **SOLELY** for the purpose of going to the F8 menu (i.e To do System Restore or System Recovery (from a Recovery Partition on the PC's HD, not from Media) or Startup Repair AND NOT TO REINSTALL VISTA. This can be needed when pressing F8 at PC boot does not take me to that menu because the PC has serious enough problems that F8 boot fails. Booting from the CD runs the programs (partially) from the CD and can be an alternative in some situations.
(2) If the PC has Vista Business or Ultimate 64 bit will the above still work (i.e CD is Vista Home Premium not Business or Ultimate). I ask because I am not sure the customer PC has Vista HP or Business or Ultimate (I have not been onsite yet).