What you have done is the soft reset. Palm has 3 more types of resets.

- System or Warm reset

- Hard reset (possible removal of data from device)

- Factory reset (guaranteed removal of data from device)

Since you may loose data, I would suggest you connect the Centro to your computer & use Palm hotsync to backup your data.

The directions to do each of these resets are found on the Palm website here

http://kb.palm.com/wps/portal/kb/common/...

Try these steps & post the result (whether it worked or not) back here.