i built my dad a comp a few years back that has a socket 754 nvidia 6100/410 board that supports SATA raid. currently he only has one 160gb harddrive but likes the idea of getting a second for mirroring purposes after i explained it to him. i haven't ever setup an array so i have a couple questions... 1) if i enable raid in his bios, i'm pretty sure windows won't want to load at that point since it has no driver in place for a raid controller. how would i fix this without reformatting? can you use repair console and load a driver off a floppy somehow? 2) when i get another 160gb haddrive to match his older model, will there be any problem with compatibility between the two? i intend to get the same make and labelled size, but the model will be different. what if the new one is slightly smaller than the old one by, say, a few kilobytes?