1. Windows. Do you have a Windows license not tied (OEM) to that original laptop?
EDIT: not original laptop, but rather original PC
2. You can't just 'transfer' programs. They will need to be reinstalled.
3. Your 'files' - music/pics/videos/etc can be easily transferred, but you will need some device to do it. e.g. your current "SATA/IDE/PATA-to-USB adapter"