ok
step1; get the ssd
step2: install the ssd in the pc, unplug the old hdd! this is important
step2.1 in bios, set sata mode as ahci (again, important!)
step3: install win 8.1 to the ssd
step4: plug the hdd back in, in bios make sure the ssd is ahead of the hdd in the boot order
step5: clean old hdd data
-depending on what you want to keep and how much you want to keep you an copy the data you need from the hdd to the ssd and format the hdd completely for a fresh start or just delete the windows& program files folders. (this is where my question above made sense, if you had already the system partition and secondary then the secondary would stay and you could format the system one on the hdd once you were done copying personal stuff to the ssd - the old c would have become the ssd and the old d stayed as d but with all the hdd. yes, free space can be allocated between partitions on the same hdd)
for a nice healthy life there are a few things to do for samsung ssds (or any ssd):
-enable ahci from step2.1 can be confirmed from the samsung magician software. install it you will need it
-the os optimization tab on the magician, follow the onscreen details and do as many as you can of them (advanced tab lists them all)
-add 10% overprovisioning
-enable trim (
http://lmgtfy.com/?q=enable%20trim )
-always leave another 10% free disc space on the c drive
for better performance and if you have enough ram enable also rapid mode on the magician.
observation: the plug unplug steps require the pc to be turned off when you do the plugging and unplugging.