If you have not purchased a soundcard separate from your computer, you will most likely be using the on-board sound chip. This uses a MIDI interface called the MPU-401. However, in many modern computers, this MIDI interface is disabled.

To use this Interface you need to enable it in the BIOS:

1) (re)Start your machine, you should see a message stating press ..... to enter setup (usually the F2 or the DEL key).
2) Press the specified key as instructed.
3) You should then be taken into your BIOS setup.
3) Once into your BIOS setup, you should be able to find a section related to your Peripheral device settings (may be under Advanced).
4) Check to see what your MIDI /MPU-401 port is set to.
5) If the setting is NOT enabled, 300 or 330 then change to either enabled, 300 or 330.
6) Exit and save your settings on exit.
7) You should then see the computer restart and load windows, when it does you will most likely see a message stating found new hardware, installing drivers.....
8) Wait for this to complete, then try running your MIDI software again.
9) You should now have MIDI input enabled.

Still Not Fixed?