Unless I am wrong- doing a fresh os install. W7 will save your old install in a folder so you can go back and move files etc from it to your new os. I do not think it will let you move installed programs tho. After you have moved all info from that last install you want to keep you can delete it and free up disc space.
So plan on reinstalling all drivers and programs and security again. Your storage drive should just plug in and work nothing else needed for it. Other than might have to reboot your system after you add the storage drive. It might work right away- I do not think so tho. It is best to reboot your system after you install a new program or hardware period.
Even after converting or edit or rip lots of videos or photos or music or windows updates or after defrags or after I run security scans it is best to reboot or your system- it can seem to run slower- a reboot fixes it. It is also good to sometimes completely power off the system and let it sit off for 3 to 5 minutes and then reboot- it like resets stuff or something and systems seem to run better after that..
For some odd reason some updates like maybe flash player do not pop up until I have let my system sit completely off for a while. I reboot and flash update pops up. I use to turn off my systems when I sleep. I do not any more they run 24/7 other than my monitor will shut off after 7 to 10 minutes. But most computer probs or break downs happen when you cold start them. Kind of like a car in winter. And during a cold/ or from power off start is the only time the psu will burst power through the whole system and self checks what ever and that surge is when most folks lose a hdd what ever.
A restart and from cold power off start is 2 different things.. To power off and sit for a few minutes and restart is another. It still does the cold boot power burst or surge but the hardware is not cold from sitting off for hours..
Ok I have typed enough- hope you get it going..