First, make that a 240gb ssd or larger. 120gb may hold windows, but many other things want to go there and 120gb fills up quickly.
I suggest you buy only a ssd to start with. Defer on the hard drive until you run out of room or need to store large sequential files such as videos.
Small files such as photos do fine on a ssd. Thumbnails will open instantly.
With 500gb ssd, you may never need a hard drive at all.
Whatever, when it comes time to do the windows install, do not have any other drives attached.
If you do, windows will place a hidden 100mb recovery partition on it.
That makes it hard to ever remove the drive later since it will be required for booting.
The motherboard bios default for sata mode is usually raid or AHCI...