So I just recently bought a new 128 GB Kingston SSD from Newegg and I am planning on doing a fresh windows install on that drive and using it as my main boot drive. So this leaves me with a second SSD and I was considering different ways that I can use it.
Would it be a good idea for me to leave Windows on the old SSD and set it as a secondary windows boot drive, kinda like a fallback drive? Is that even possible? If it is, what are some problems that I may run into?
That is perfectly reasonable possibility. If I were you, I would remove the secondary drive from the computer and store it in a safe place. That way, if your computer gets physically damaged, you are only out 1 SSD instead of 2.
Or you can use the extra SSD as another program drive.