Obviously you can't do a recovery from the recovery partition when you replace a HDD. Do you have recovery disks though? Those should work regardless of the HDD unless there's an error on the DVD(s) or a physical defect on the DVD. If the product key sticker on the laptop is readable, that product key can be used to activate the version of Windows it corresponds to (32 or 64 bit doesn't matter). You can legally download a copy of Windows (or use a borrowed DVD) and use the key that came with the laptop to activate.