I have a 2011 Mac Mini with an original 500g HDD and a 120g SSD that I installed recently. OS X and all apps are on the SSD and I only use the HDD for Time Machine. I also have a 750 HDD external that can be used for Time Machine. I need to run Office and Quickbooks on a PC (can't use Mac version). What are my most economical options here? I prefer not to mess with the SSD, but the HDD is open game (will just use the 750g for TM).