I hv palm treo 750 and it stock on logo

check soft ware at first , then hard ware solution by cleaning the board , be sure that keyboard is clean enough.....

Hello,

Soft Reset
A Soft Reset stops all active (or open) programs and "reboots" the handheld. When the Treo powers back up, you'll start with all programs closed and the unit will be ready to use. The soft reset is intended to reset the Treo if it is malfunctioning or has become bogged down.
The Palm Treo 750 can be soft reset by quickly pressing and releasing the tiny red button beneath the miniSD memory card door:
Hard Reset
A Hard Reset wipes the internal memory and returns the Treo to its factory specs, in effect returning the Treo 750 to the state it was in when you purchased it. All data entered, preferences set or software installed on the Treo after purchase will be lost after a hard reset and will have to transferred or reinstalled via ActiveSync / Windows Mobile Device Center.
The Palm Treo 750 can be hard reset by pressing and holding the power button (seen left) while at the same time pressing and holding reset button beneath the miniSD memory card door. Press and hold the two buttons until the screen completely fades. When the screen returns, you'll be given the option to "Erase all data." Select Yes to complete the hard reset. The Treo will now be as it was when it left the factory and you can start fresh. You may have to perform a soft reset after the hard reset to get the unit to power on.

When you see the first screen (the orange one) hold the UP button as the bar moves across the bottom of the screen. Let go right before the screen goes to the silver logo. If it continues and opens Prefs, then you need to delete the program causing it to reboot. If that doesn't work, do a Hard Reset. A Hard Reset will erase everything on your Treo, so only do it if you have to. Google how to do it, and it's reset.

my favourite (treo 750) i own 1 but not sure i have had that problem yet depending on if you install a program it could be causing that problem maybe a call blocker! u could check to see if ur network is on automatic
start-setting-personal-phone-network-netselection automatic
try backing up your phone data then master reset back to factory setting
N.B you would loose everything that cannot be backed up but this solved my bluetooth problem 1 time holding down the reset button then press power. when prompted to reset say yes

Soft reset = push button behind the SD card door with stylus.

Hard Reset (WILL ERASE ALL DATA) = push same button after holding down the red phone button.

There are multiple reasons for the phone to go into an endless loop.

Fix #1 - Soft Reset - Take out the battery. On the back of your phone, pop the cover off, remove battery, place battery back in and it will show each screen once and power on normally.

Fix #2 - Hard Reset - To do a hard reset, hold the power button while you replace the battery and then release it when the Palm logo appears.

Fix #3 - Hammer

A Hard Reset wipes the internal memory and returns the Treo to its factory specs, in effect returning the Treo 750 to the state it was in when you purchased it. All data entered, preferences set or software installed on the Treo after purchase will be lost after a hard reset and will have to transferred or reinstalled via ActiveSync / Windows Mobile Device Center.
The Palm Treo 750 can be hard reset by pressing and holding the power button (seen left) while at the same time pressing and holding reset button beneath the miniSD memory card door. Press and hold the two buttons until the screen completely fades. When the screen returns, you'll be given the option to "Erase all data." Select Yes to complete the hard reset.
The Treo will now be as it was when it left the factory and you can start fresh. You may have to perform a soft reset after the hard reset to get the unit to power on.

There is a treo repair website that shows you how to replace the screen yourself.

There is another reset that is designed to stop the Treo from looping. System(warm) Reset. Make sure you have the battery charged fully or plugged in before doing this one. It is available on the Palm.com site. Select your model and look for troubleshooting or type System (warm) reset into the search bar. It also concludes with a soft reset. Here is the short version: press and hold the UP button on front panel and also press and hold the sylus in the reset button. Hold both of these until the second Palm logo appears. Then release the UP button. Then, the reset button. Now do the soft reset(batter out then in).

If your Treo loops or freezes during a soft reset, a system reset may help. Performing a system reset allows you to get out of an endless loop in order to uninstall a third-party application causing the looping: 1. Press the Battery Door Release button and slide the battery door downward to remove it from your Treo. 2. While pressing and holding Up , use the tip of the stylus to gently press the reset button on the back of your Treo. 3. When the Palm Powered logo appears, release Up . 4. Delete the third-party application that you suspect is causing the problem. 5. Perform a soft reset. The wireless features of your phone are not available until you complete this step. Good luck!