If the "Code" and "D" keys are not working on your Brother Word Processor WP-700D, follow these steps to troubleshoot the issue:

1. Check for Debris or Dirt: Gently clean around the keys using compressed air or a soft brush to remove dust or debris that might be obstructing them.

2. Test Other Keys: Ensure that other keys are functioning properly. If multiple keys are unresponsive, there may be a larger issue with the keyboard.

3. Power Cycle the Device: Turn off the word processor, unplug it, wait a few minutes, then plug it back in and turn it on to see if the issue resolves.

4. Check for Key Sticking: Press the affected keys multiple times to see if they feel stuck or unresponsive. If they are stuck, gently press around them to loosen any obstruction.

5. Inspect for Physical Damage: Look for visible signs of wear or damage on the keyboard. If the keys appear physically broken, they may need repair or replacement.

6. Reset the Word Processor: If possible, check the user manual for instructions on resetting the device to factory settings, which might resolve software-related issues.

7. Check Internal Connections: If you are comfortable opening the device, check for loose or disconnected ribbon cables that connect the keyboard to the main board.

8. Consult a Technician: If none of the steps above work, the keyboard may need professional repair or replacement.

If the issue persists, contacting Brother support or seeking a repair service may be necessary.