Windows does not support booting from an external drive so just changing boot order in bios will not allow your cloned disk to boot. There is also the issue of the cloned drive containing bootfiles configured for an internal rather than external drive Your best option is to get a new replacement for the internal drive and re-clone to that new internal drive. In Windows at least, external drives are useful for storage but not for operating system installation.
Those processes that enable booting a windows operating system from an external drive do not apply to a cloned operating system disk. You would need to install the operating system to the external drive and it would then only work on the machine it was attached to. Msoft does not support that configuration. http://www.ehow.com/how_4853554_ins...
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