Nope, the hard drive has its own interface, most like some version of SATA unless it is REALLY old.
What Hemi-Cuda posted or what you posted should both work, I have one of these:
http://www.memoryexpress.com/Products/MX39503 just because putting in bare drives is something I do enough of that I don't want to have to open and close an external enclosure over and over.
You could check NCIX or Direct Canada, and if you find something cheaper Memory Express will pricematch. Or use shopbot.ca to do some price comparisons, Newegg.ca has the one HC posted for $20
http://www.newegg.ca/Product/Product...INC-_-12156102
No to both for having to uninstall to use the product key again. For Office you should be fine with installing it and activating it, with Windows 8 that's more complicated, if you're putting it on a completely new computer, you might have to phone in to get it activated (I've had to do that before, they just ask what happened and I told them I was rebuilding the computer with some new components, which I was, be honest).
With previous versions of Windows the OEM versions weren't supposed to be transferred from one PC to another while a full version could, I'm not sure if this restriction still exists in Windows 8. If you got a full version or upgrade version you will probably be ok, but if you got an OEM version it might not be movable.