Well, the only thing you would have to do is to connect both drives to your PC and: enter the 640GB drive, press Ctrl+A, Ctrl+C, and then open up your 2TB drive and press Ctrl+V. And then wait about a million hours.
As for data, this is everything. But for installed programs it's a tiny bit more complicated - these guys get their own Windows registry entry pointing to the place they are (or were). For them to work absolutely identical as before, you just need to make sure that the localisation of the programs is just like it was before.
(640GB drive) -> D:/apps/myprogram
should be copied to
(2TB drive) -> D:/apps/myprogram
I just need to remind it, if both of them are working together in the PC, 640GB drive gets designation D, and the next one (2TB) will be named E (or the other way). And if you disconnect the 640GB one, 2TB will take its letter (and for example, become D). I think drive letters and partitions aren't that hard to understand...