The first task is to define our terms. It's impossible to reason about anything without a good grasp of terms.
So, for example, if by "consciousness" we mean "intentionality" or at least that it entails intentionality, then you have to explain a) how anything within a computer can be about anything in the world, and b) how abstract concepts can exist in a computer. And you have to think very carefully about this because the internet is full of flippant and unexamined responses that confuse the interpreter with the interpreted.
Let's say I take a picture of a bike wheel and store it on a computer. What makes this about the bike wheel? I know that the picture is about the wheel, but the picture does not contain that information. No "metadata" can accomplish that either because metadata is of the same nature as the image. Metadata isn't even intrinsically about the image in question. It's there, maybe adjacent to it, but its aboutness is, like the image's aboutness, entirely in my mind. A program can be written to simulate aboutness, but again, the aboutness is simulated in the sense that it is not a real feature of either the metadata or the program. It is an interpretation the programmer or user brings to the computer. So again, no aboutness is to be found in the program either.
Then there's the question of abstract concepts. A wheel is a concrete thing, but to know that it is circular is no longer a concrete matter. Circularity is nowhere to be found in the world as such. All you ever have are particular circular things. The concept of circularity requires abstraction from particulars. So why can't a computer do that? The reason is the same as the reason why circularity does not exist in the world on its own and that is that matter is always particular. Matter is not abstract. But computers are material things. So how could a computer abstract circularity from an image of a wheel? Sure, you can have an algorithm that is written to match circles in images, but this is not the same as having a concept of circularity on its own. For that you need an intellect.
The problem of qualia is also related. A materialist account of physical reality entails the denial of qualities like color because all that a materialist accepts is a world of geometric extension in space. Qualities are therefore taken to be features of consciousness. But if consciousness is a physical phenomenon, then how can that be? Here again computers provide no answer. Sure, I can represent the color "red" using #FF0000, but this is not the color red. I can construct a monitor that, when fed a signal that corresponds to #FF0000 activates some physical elements to produce red light, but this is just a conventional alignment between that representation and the construction of the monitor. There is nothing intrinsically red about #FF0000. And besides, the monitor isn't really producing red light according to the materialist. It is producing light that is in a state that, when observed by a conscious being, appears red (which, again, runs into the problem of how even that is possible given that consciousness is physical).
So the whole idea that computers can be understood as truly autonomous things apart from human beings is bankrupt. They are better understood like all other technology: an "extension" of human beings. While most animals have all they need in themselves to achieve their ends, human beings can construct technological artefacts to perform actions that they could not otherwise. A turtle has a shell to protect himself, but he is also limited to that shell. Human beings are on the other hand lack any such protection, we're soft and easier to hurt, but we have a mind that allows us to make protection when we need it and in an (in principle at least) uncountable many ways depending on the needs facing us. We make coats for winter weather, astronaut suits for the low-pressure environment of space, a beekeeper's helmet when extracting honey from hives, and so on. Computers are just another expression of the same principle.