What are the chances that your phone may already be running too low in phone memory?
The continuous reboot is often as a result of this.
I had it once on my Droid Incredible. The best solution was to do a hardware reset. Press the power button and the volume control button simultaneously as it starts.
It will reset the phone to a clean state. The OS version will remain on the last version you upgraded into, not the original OS that was out of the box.
You may lose some data but:
1.) Your contacts are backed up with Google. Sign in with Google again and your contacts and calendar will be synced back and restored. This is assuming you let Google store your contact data.
2.) The Android Market will always remember and mark your paid apps as Purchased. They will be free to download again.
3.) The reset will not erase any data on the micro SD card.
4.) Your GMail is stored and restored from the Google cloud as well.
You can lose the history of your text messages, any POP3 email on your phone, unless the POP3 account is also on your PC, and you have downloaded your email to your PC. YOu will have to download your apps one by one again, but this time, don't include those you don't use much and make sure you keep an eye out of your phone memory.
If you're hesitant and want a second opinion, you can bring the phone to Sprint.
There are some apps you don't particularly install on a phone with limited phone memory space. One of them is Twitter for Android.
I am running stock 2.1 for the sprint HTC Hero, and my phone was running just fine last night. When I went to bed, I plugged it into the wall as asual left on. When I woke up this morning, it is going through a continuous reboot cycle. It gets to Sprint "NOW" screen and starts over....I have no idea what to do....i honestly didn't do anything to it!!!! PLEASE HELP ME!!!!