text: how doesit work?when we type a in keyboard  , then the alphabet a appear in your screen? i mean how computer work..its really wonderful.. when you press the key down, an electrical circuit is completed, which sends an ascii or hex symbol back to the computer, which interprets it as a specific number or letter.  some computer viruses can mix these signals up, and replace the key a, with the ascii symbol for hte letter o for example.. so everytime the person presses a, the letter o shows up.