First thing to know is whether the HD you intend to fit was
originally installed on this hardware ? If so, then you should just be
able to plug in then boot up - the Linux loader should detect the new
OS and add it as dual boot automatically.

If the drive came from different hardware then the loader will still
create a dual-boot but it's a bit of a Turkey Shoot as to whether
Windows will boot up or not.

As for finding information about the hardware, there are tools to do
that and basic info is available in System Monitor or go to Ubuntu
Software Center and search for Sysinfo.