Adrian
When you input the wrong config register value you changed the speed of the console port. You can recover from this by changing the speed in your terminal emulator (Hyperterm or whatever you use). I suggest that you try all the speeds, starting at 1200, 2400, 4800. In some terminal emulators (especially Hyperterm) you may need to stop the emulator and start the emulator each time that you change speeds.
When you find the speed that works, you will be able to set the config register to 0x2142. At that point you will need to return your terminal emulator to 9600 as the speed.
HTH
Rick
HTH
Rick