My old laptop died and I took out its Hard Drive which is now readable on my new laptop using a USB caddy. I can access all the files fine - but not run programs from it. I gather I need to boot from the old HD to run programs from the old HD. OK, so I've gone into boot options on start-up but my USB HD does not show, even though USB boot is enabled. I've altered the BIOS so that USB boot is first, I've removed the USB printer connection and I've swapped the caddy to another USB slot. But no change - although this HD booted just fine in its old machine, it is not booting when attached to this new machine. Is there something else required and if so, what?