The bitcoin folder under program files doesn't have a wallet.dat file, that's what is confusing me.
A new installation of Bitcoin doesn't come with a wallet.dat
Each time the bitcoin client is launched it checks for wallet.dat. If none exists, it will create a new one.
So simply copy your wallet.dat from the backup to the Bitcoin data directory and launch Bitcoin. It should load the wallet.dat just fine, even though it is from a prior release.