- For the kind of "Computer" you can hack into, see Terminal.
Computers are the only Buggable Furniture in both the above-mentioned rooms. Since bugging these rooms gives the best possible Surveillance Quality (+8% and +12%, respectively), Computers are by-and-large the best possible piece of Furniture to place a bug in, if you can find them.
To bug a Computer, walk up to it and press the "F3" key. You will need at least one Bug remaining in Max's inventory to do so.
You can hide behind a Computer even without crouching. It is impossible to jump over a Computer.
Computer vs. TerminalEdit
Note that the use of the term "Computer" to describe this piece of furniture can be considered outdated and may be confusing.
A 2x2x2 meter cube standing in the corner of a room is what we would nowadays call a "Mainframe" or at least a "Server", but the game refers to it as a "Computer". This piece of furniture can only be Bugged - you cannot interact with it in any other way.
On the other hand, the desktop-variety computer, the kind we're all familiar with, that has a keyboard and screen and all that, is referred to in-game as a "Terminal". That is the piece of furniture that can be Hacked into by Max to retrieve information.