I was in the middle of a call when the cell phone just shut off. Now on restart it only shows the Hellomoto symbol and then flashes a white screen. Is it fixable?

It it shows the white and green HTC logo boot screen...then shuts off or loops....this seems maybe software issue.
It may need re flashing of the rom.

I confirm that tiggywiggy's solution works. Just pull out the battery and hit it with your hand.

many imported phones need to flash their sofware to unlock it.

I think it was not correct. if the flashing is not correct it shows these type of errors.

So try for a better BoX Flashing

You have a couple of options:
Take it to a motorola repairer or try to update the firmware on your phone. As you cant get it to go past the Hellomoto screen a hard reset would not possible.

your firmware is corrupt, the only way to revive your phone is re flashing it.Its hard to do, and by doing it wrong may damage your phone. To safely retrieve your phone is let the experts do it or go to a near cell repair shop and let them help you out,

if you want to do it your self, try this

first you need is a RSD lite program or flash and back-up to flash or reformat your Motorola,

to enter the bootloader

hold * then the # then power button, your phone will boot to bootloader, and you will see there the flash program of your phone,

start the program rsd lite or flash and backup
then connect it to your computer VIA usb, automatically the program will detect your phone,

i prefer that you first buck up your firmware by using F&B (Flash and backup) then use RSD lite to flash your Motorola,

RSD lite its much easier to use than F&B, but for safety backup first your firmware,

gudluck

I guess you didn't bought it from cellular phone company, in that situation go to a cellular repair. The problem is that the fuses no working right or the parts are horn and week

Hangs on "Hellomoto"
Motorola Software Update (MSU) located on the Motorola website:
http://direct.motorola.com/hellomoto/Motosupport/source/SoftwareUpdateSelect.asp
This should upgrade your phone’s software and restore functionality of the phone.

The phone somehow got some corrupted firmware files. - It can be fixed with a simple flash - a service center should be able to do it for you - cost should not exceed $25

If you need more info
http://horizonwirelessonline.com

gets stuck on the symbol? Do a soft reset @ + 1 + 0 and hold down the W or you can pull the battery out and place it back in while holding the W and see what happens when you startup while holding W. __________________
credit: Sweet Peaches vbmenu_register("postmenu_999614", true); http://www.poweredbydanger.com/forums/showthread.php?t=97974

take out the memory card and try restart...if works then format the memory card (contents will be deleted..take back up) and reinsert...otherwise reload the phone software..