Since Armory wallets are deterministic it doesn't matter if you made the backup when you first created the wallet. All of the information will still be there when you restore the wallet to a new machine and no need to copy any files.
Any notes you have added after taking the backup will be lost. But no BTC will be lost.
You may actually want to copy over both the full Armory data directory, and the whole Bitcoin-Qt data directory. The latter will save you a 1-2 day synchonization of the block chain. Unfortunately, I never use bitcoin under Windows, so I have no clue where the data is hidden.