A soft reset is similar to restarting a desktop computer. It's the most useful trick in your toolbox for fixing a variety of issues.  Soft resets usually do not affect your personal data on your device, unless your battery is low. If see battery warnings, change or charge your batteries immediately even if there is an error message onscreen. Also, it's a good practice to perform a HotSync operation before any reset (assuming that synchronization is not the problem you are trying to fix).

        
   
Turn off wireless mode by pressing and holding the red Power/End key .
Remove the battery cover on the back of your smartphone.
Take out the battery.
Put the battery back in.
Replace the battery door.
After a soft reset, a logo screen appears, followed shortly by a Preferences screen asking you to set time and date.

If a soft reset does not resolve your problem, you may need to try one of the other resets below.

What's a system reset? A system reset tells your device to stop what it's doing and start over again, bypassing any system extensions. This can help you with "boot loop" errors, allowing you to remove any recently installed third-party applications that might be causing the problem.    Be sure to perform a soft reset at the end: Certain features of your device, such as HotSync and some wireless communications, will be disabled after the system reset. You need to perform a soft reset to enable these features again.
 

Press and hold the UP button on the front panel of your device.
While holding the UP button, use an unfolded paper clip, or the reset tool at the tip of your stylus, to gently press the RESET button inside the hole on the back of your device.
Treo 680: There is no RESET button; instead, remove the battery and replace it while holding the UP button. It helps to remove the battery cover (but not the battery) before starting a System Reset, so your hand is free to hold the UP button throughout.
The Palm Computing Platform screen will appear. Release the UP button when you see it. Depending on your device, pictures of the logos are shown below:
     

On some devices, you may see a Palm or palmOne logo and a progress bar first. Do not release the UP button until the second, circular Palm Powered logo appears.
    

Because this reset is a bit awkward to perform, sometimes it doesn't actually happen when you think it does. Test to see if it worked:
Open the Applications launcher. Access the General preferences (on some devices, you may need to access Power).
Tap on the pick list for Beam Receive. Choose "On." If it still displays "Off," then your device was correctly system reset.
Once you've tested that the system reset worked, perform a soft reset. Otherwise, some functions will not work.
Sometimes a system reset fails to break out of a loop. These extra steps may break the loop without having to perform a full hard reset.

Perform the first part of a hard reset but stop when you see the option to press UP to erase all data.

Then perform a system reset as described above but make sure to depress the RESET pin first and then the UP button;  otherwise you will complete the hard reset. Be careful! Don't accidentally perform a hard reset, or you will lose all data on your device.