There are two types of reset on the Proteus 2500. One is the "Init to user data" which resets everything, and you will lose the factory preset patterns (available on the CDrom that came with your unit), and the other is "Init to user data except presets" which preserves factory preset patterns but initializes everything else. The second is the recommended type of reset.

1. Turn on the unit while holding both Cursor buttons down.
2. Once booted up into Diagnostics, turn the Data Entry Control Knob until you see Initialize User Data except sequence data.
3. Press the Enter button.
4. Press the Enter button again to verify that you want to initialize you unit.
5. Now, turn the unit off. Wait a few seconds and then power-up the unit normally.