I dont have arma 2 in the expansions

It came up with 1 file failed to validate and will need to be reacquired for both on the verify

It doesnt have Arma 2 on the list just ca Arma 2 OA BAF PMF and (@dayz but i have installed it yet?)

i got up to lauching both through steam but it doesnt link arma 2 to OA? what should i do or is that fine?

I download combined ops from steam, it gave me Arma II, Operation Arrowhead and the beta as seperate games, I decided to install dayz but it doesnt have lauch Combined Ops and it is missing some Chernarus file and a citizenscope problem? Can someone help please.