Why wouldn't they function together? As far as the OS is concerned, they're both storage devices, it's up to the device's hardware to take care of the rest. You seem to be overthinking this by quite a bit.
I intend to buy a new budget computer system shortly.
It has a 60 GB SSD SATA 2 and I have a spare Seagate 500GB SATA 3 drive. Will the two drives function together?
If not, I'll just have to get another 500 GB SATA 3 drive.
Another problem is that all my data/music /photos has been saved on a SATA 2 external HD. Will I be able to transfer it to a SATA 3 Drive okay?
Finally, can the image tool in Windows 7 do a full system backup if two drives are installed?