how to switch between disks without dual boot

Hi there

For me the EASY way to do this would be to choose the Boot disk order in the BIOS -- a lot of BIOSES now give you a short BOOT menu without having to go into the whole full blows BIOS menu. Pressing something like F8 for a boot menu is simpler than anything else. A BOOT menu doesn't permanently change BIOS settings.

Things like EASY BCD are a pain when you need to re-install / upgrade windows or have things like UEFI / GPT disk drives. I'd try and avoid those types of solutions.

However instead of dual boot -- especially if one of the systems is XP -- why not use a VIRTUAL machine -- IMO much simpler and unless you have very tricky hardware or really weird applications you should find modern releases of Virtual machine software will boot up a virtual machine and run pretty well all your applications on it with barely a noticeable degradation in performance. VMWARE's vmplayer and ORACLE VBOX are both free - my favourite is VMware's offering but both run XP VM's just fine.

Have a read on VIRTUAL MACHINES -- IMO better all round and you don't need to re-boot the machine to switch OS'es --you can also have BOTH OS'es running CONCURRENTLY too.

Cheers
jimbo