It is most convenient to use a computer as a musical instrument by connecting a MIDI keyboard to it.
But if it's not there, you can play on the keyboard for typing.
Install the program on your computer,Allowing you to use a regular keyboard as a music keyboard. Which one depends on the operating system installed on the machine. For Windows, for example, PC 73 Virtual Piano Keyboard, KeyMusic. The first one allows you to play both on the physical and virtual keyboard, the second one - only on physical, but has a more interesting feature: it works in the background, and notes play even when you type characters in any other program. There is also the Analogx Vpiano program, but it works only with a sound card that has a hardware MIDI synthesizer, or its emulator.
In Linux, you can run any of the abovePrograms through the Wine emulator. If you are not comfortable with this, use a similar application designed specifically for Linux, such as Vkeybd or Jack Keyboard. Both, like Analogx Vpiano, require a sound card with a hardware MIDI synthesizer or an emulator of such a synthesizer (for example, Timidity).
To play the virtual piano right in theBrowser, go to TheVirtualPiano or Virtual Piano Keyboard Online. The applications are implemented in Flash and compatible with all platforms where there is a Flash Player, including Linux, Windows and Mac OS X. They allow you to play chords, calling each of them with a single number key.
Regardless of which of the programs you choose,Read its help with the correspondence of the keys of the computer keyboard to the notes. There is no standard here. If the program allows you to reassign keys, use this function if you want, by selecting a convenient location for notes on the keyboard.