Sidekick id big red x

Yeah, more than likely the lcd cable connection is loose. That is what the white screen usually indicates.

It is fairly easy to take a apart and reseat.

Follow the guide at the link below

Fix Sidekick 3, Sidekick ID, Sidekick II White LCD Screen

HOW TO DO A MASTER RESET ON A SIDEKICK 3 NOTE: Performing this will restore your device back to factory defaults, meaning you'll loose everything on your sidekick!
1. Remove the battery and the SIM card from the device. 2. Flip the sidekick open; press and hold the letter 'r' on the keypad. 3. While holding the letter 'r', place the battery back in the device. DO NOT INSERT THE SIM CARD YET. 4. The sidekick will restart itself twice. Please make sure not to let the letter 'r' go until it has fully rebooted. 5. Once it has fully rebooted, remove the battery, re-insert the SIM card and battery and power up the device. 6. Once the device has fully rebooted, all prior information should be erased from the device and it should be restored back to the default factory settings.

you need to get a new battery.

I found this guide online.
Please let me know if this works!

"1) Insert the ATT SIM card into the back of the T-Mobile Sidekick ID (it should be located behind the battery).

2) Turn on the Sidekick ID, wait for the screens to load.

3) When the screen says "Waiting for Activation", hold the top left button (the "Menu" button with the three lines) on the Sidekick ID and hold the letter "L" on the QWERTY pad at the same time. After a few seconds, let go of the buttons.

4) If Step 3 is done correctly, the Sidekick should be directed to the jumpscreen and display all of the Menu's of the Sidekick ID.

buy a new phone.

try a friends battery if that doesnt work then dont buy a battery and sometimes reseting the phone may work like turn the screen to 90 degress and put an earing or pin inside the reset whole

Sounds like your charger port is busted. Ti is a common problem on sidekick 3 and can effect sidekick IDs as well. A fairly cheap workaround is to get an external battery charger. It will have a slot to charge the sidekick battery external formthe phone. They sell on ebay fior about 25 dollars.

The sidekick ID and sidkeick 3 batteries are the same so it will work. Check then out here

Sidekick ID battery charger

ok the exacct same thing happened to my phone... what i did was i kept taking out the battery, and seeing if my phone would work. there r few things that can happen everytime you take out the battery aand put it back in:
-it will show the menu button (the bottom left button on your phone) in black and white
-itll show the red x again
-the backlight might or might not turn on
-itll start up and work normally
these things will happen everytime u restart ur phone affterwards, and, usually, ur phone, even if it starts up, will go really slowly and eventually freeze, forcing u to repeaat the battery cycle.

after a while, it became worse, but, after fdoing thte battery thing over and over, it finally started up, and took me to a reboot screen, where it showed me a tiny clip art pic of a sidekick with a =P face that was broken. then it showed me the reboot screen, asking me if it wanted me to reboot, and, afercliking yes, it starteed working again

Firmware crashed. T-mobile needs to reload the OS into your device. Its "blank" or corrupt. Only way to bring the device back is to flash it

You can try hard reset to see if that will clear it. With the unit powered on, pull the battery out.