You are a little muddled with the terms and concept of the hardware.
The primary (boot)
drive, mechanical or SSD, (in your system the OCZ Agility 120GB) is
device that contains the operating system, programs and DATA.
When you open a word document and start to work on it, Data is sent to the processor and to the RAM, (memory)
After finishing the work the Date is then written back to the HDD.
AS you think there is not enough room left on the Primary drive, you are correct in your decision to install a second HDD, (slave)
for more space to store Data. NO OS is installed on this drive.
The Intel 80GB SSD is not really a very good choice, to small, you will fill it in no time if you have lots of music and films. Dollar per Gigabyte, very expensive.
If at all possible, you should return the SSD drive and get one with more space (capacity
), This is the one I use for my storage drive, > http://www.newegg.co...N82E16822148840