Hi all,
I had this same problem with the Sprint Treo 700P. This was my fix.

1. Do a WARM reset. A soft reset and even hard reset did nothing for me, but a warm one did. Here's how:
http://kb.palm.com/wps/portal/kb/com...le/887_en.html

NOTE: IF your phone does start up this way, it is definitely a 3rd party app that's messing it up and NOT a hardware issue. You will know this because a warm reset is just the essential OS with no 3rd party apps working. You will see them, but they will not be functional. DO NOT LEAVE YOUR PHONE THIS WAY. It's not fixed yet.

2. Delete the suspected apps. I'm pretty sure mine was a 3rd party keyboard app that is used to enable an infared fold-out keyboard. If you don't know which one it is, if it's possible, delete all of your 3rd party apps. Sorry.

3. The directions I read said to soft reset again, but that didn't work for me. It just started looping again, so I warm reset it again, deleted more apps, rinse and repeat. So I got lucky with something else...

4. Finally I tried to turn the phone on to see if it would work in warm reset mode until I figured out how to fix it. The phone restarted and came up fine! So, if the soft reset isn't working, try turning the phone back on while you're in warm reset mode (red button on the right front that you normally use to turn the phone on and off).

5. I agree with the instructions on the other sites - DO NOT ATTEMPT TO SYNC UP TO YOUR OLD PHONE COPY. Unfortunately one of those apps you synced with is hosed and this will happen again if you resync.

a. Instead, save a copy of your old phone backup somewhere and then delete it from your Palm Desktop. Then sync again like a new user and make sure your settings are to back up your phone to your computer.

b. Then go get the 3rd party software (Google it if you had it beamed to you originally) and go download it. Get the latest version, as they may have fixed the bug that made it hose Treo's to begin with.

Good luck! This happened to me once before and I assumed it was a hardware issue so I got the phone replaced with Sprint's Equipment Protection Program. The co-pay went up to $100 through Sprint, so I dropped the plan. When it happened again only a month into having the new phone, I decided to see if it was software and it was. The likelihood of hosing exactly the same on two machines is either a major hardware defect on all Treo's, or *more likely* a 3rd party software app of something you put back on the replacement phone.

Hope this helps.
KD