First about legality, Microsoft always bashed the point that is THE STICKER that make the installed copy legal or illegal, so as far as you have the sticker license on your PC, you can use any way and any system for install the OS on the pc (dvd, flash, original, copied, also telepathy, if you're able to do it in that way
)
Second about functionality ..... if you have XP ..... STAY ON XP :beer: ..... Vienna (win7) is also more crap, failed and bad working than Vista, and Vista was a complete fail itself :na:
And if you want a proof, think to one thing only ..... Microsoft had always stated, when Vista was launched, that after 31 dec 2009 there was no more XP copies available, cause the "new advanced operating systems" Vista and Vienna was substituting it in anything, so they said, no more XP was produced nor selled, after that date ..... well, it can be, but in this case, why after a pair of months from the release of Vienna, Microsoft re-introduced XP, saying that production and selling of it was prolounged til 2012 ? .....
cause Vienna was working too good, i'm sure .....
:eg: :na: :crackup: