SampliTron is a virtual software sampler instrument designed for live play. It can be controlled via the computer keyboard or with an external MIDI device. It includes a library of high-quality .WAV samples.
Portable RMCA Pro is auto-accompaniment software which offers all major features of a high quality MIDI keyboard. Take RMCA Pro with you on your USB Stick or any other portable media; runs from stick. Installs itself in one directory tree.
In FlexiMusic Orchestra you assign "small pieces of music beat" to each key/button of all your "Input Devices" and play it as orchestra or musical instrument.Small piece of music beat: You can use any standard instrument/drum from midi bank.
Convert your PC into a Piano. With Little Piano you'll be making music in no time. Using its simple interface, you'll be able to record songs, use multiple instruments, and share your songs.
Softboy.net On-screen-keyboard can be useful if you have mobility impairments, if you are using a tablet PC, or if your keyboard goes down. And it can works well on touch-screen. This a demo keyboard which includes the main keys on a normal keyboard.
Java_Sound is a Java program that lets you use mouse or computer keyboard to play piano and record sounds with more than 100 MIDI effects. You need to install Java first, get Java free at : http://java.com/en/download/index.jsp
SigmaTizm is a virtual additive synthesizer instrument designed for live play. It can be controlled via the computer keyboard or with an external MIDI device and can also be used to control external MIDI devices.