no need leh
I just copy the whole D3 file from program files to portable hard disk

and paste them to ur new window..under same directory

after that just run the launcher and it will auto download few patches and ready to go
It did came out with few error but the launcher fix itself

that work for me ..but don know if it works for u

can gehI also transfer from win 7 to win 8 mah
try it...
if cannot then use old fashion way lo...