What would be the best, yet least expensive version of Windows 7 (possibly Windows Home Edition or Premium??) to install on this HP Pavilion s5213w. Also, I would like to be able to use this same software purchased on an older model Dell that does have the minimum requirements to run it. However, my older computer is 32 bit and the HP Pavilion Slimline is 64 bit. Will the 32bit run just as well on the 64 bit machine? What are the downfalls/disadvantages?