control panel, administrative tools, services, in that list you will find superprefetch right click and set it to stopped. it will stop the vista machine from taking a long time to boot, and will not populate 80/90% of the memory you have installed. indexing is in tha same list, do the same to that.

vista loves memory. 2gb is good 3gb is better, but if you are running 64bit then upto 8gb

as said before. keep programes on c: and keep the second drive for video. when you put the new drive in, vista will format it into ntfs simple, the system you get will have sata hd interface so1 hd will be more than able to deal with sd and hd.