I just did a new build for a friend that wanted two 2tb drives for storage that are not being seen by the computer; however they seem to be installed. His o/s is windows 7 pro on a 320 gb drive. Anyone have some advice. Sure would help
That is exactly right. Any new HDD unit is just empty space with no organization. Before you can use it, you must first Create on it a Partition - that is, specify a block of space to be used as one "drive" with its own letter name. You can make it any size, up to the full size of the whole disk. Or, you can make it smaller and later Create another Partition to be used as a separate "drive". Then for EACH Partition created, you must Format that Partition - that is, you actually install a File System that controls use of the space assigned to that Partition.
Many tools for doing these two steps combine them into one to make it easy, sometimes calling the whole process "Initializing" the drive. So how do you do this? Windows has a built-in tool called Disk Management. You use its LOWER RIGHT pane and RIGHT-click on a new drive block to access the mini-menus for this. Or, you may find it easier to download from the website of the HDD manufacturer a utility of prepare a new HDD for use in Windows.
But note that in Win 7 the two steps, Partition and Format, may all be combined into one so that you set all parameters for them at once before executing the process. You will need to so this once for EACH Partition you Create on EACH new empty HDD unit. (You probably will choose to make only one Partition per HDD, each using all the space available.)
IF you are considering making several Partitions on a drive, just remember that you are allowed a max of 4 Primary Partitions on one HDD. If for some reason you need more, read up on how to make Extended Partitions.