I shut down my sony xperia and now its stuck in power down mode

hi there.
not sure if this is your phone as you did not give model number.
but try this.
First method:

1. In order to switch off the phone hold down the Power button for a short while.
2. Afterwards go to Settings and then to Backup & Reset.
3. Then selec Factory Data Reset and tap Reset Phone.
4. Choose Erase Everything if you are sure you want to clear all your data.

More items...

SONY Xperia XA F3113 - How to Hard Reset my phone - HardReset.info

www.hardreset.info/devices/sony/sony-xperia-xa-f3113/
or this one.
Restarting andresetting your device Sony Xperia XA support Canada English
or this.
Restarting resetting and repairing Sony Xperia XA support English
or this.
SONY Xperia XA F3113 How to Hard Reset my phone HardReset info

you need to get the phone in boot mode you could try this power off the phone after powering off hold down the power button and volume up button (volume down) at the same time you should get into a boot mode use the volume button to select wipe data and factory reset then press the power button and then select yes and allow the process to go through

restore settings

or this one note all data will be deleted

How to Soft Reset or Reboot or Restart SONY XPERIA T LT30p ?
To soft reset SONY XPERIA T LT30p, press the POWER BUTTON KEY for several seconds, we will see the menu to restart or turn off. Choose restart/reboot than the SONY XPERIA T LT30p will do the soft reset or restart. This is safe to do because non of important data or applications will wipe or erase.
#Option 1, Hard Reset SONY XPERIA T LT30p with Software Menu :

1. Make sure the battery is charge properly
2. Turn on SONY XPERIA T LT30p smartphone
3. Don't forget to backup all important data
4. Go to menu: Setting > Backup & reset > Factory Data Reset > Erase internal storage > Reset Phone
5. Choose Erase everything to continue and confirm you ready to do the format SONY XPERIA T LT30p
6. The SONY XPERIA T LT30p will continue the step until ready to use in clean factory default.

#Option 2, Hard Reset SONY XPERIA T LT30p with Flashtool applications:

1. Flashtool in the applications from Sony can be download from Sony website.
2. Flashtool software need to installed in you computer and ready with USB data cable
3. Make sure SONY XPERIA T LT30p battery is charge properly or full charge
4. Power off SONY XPERIA T LT30p
5. Boot SONY XPERIA T LT30p to flashmode with using: Volume Down Button and connect to USB cable at No.1 above
6. Follow the menu at you computer display, it is easy to understand the steps.

#Option 3, Hard Reset SONY XPERIA T LT30p with Hardware Key Button:

1. Make sure the battery fully charge
2. Do not forget to backup all important data
3. Turn off the SONY XPERIA T LT30p
4. Press and Hold together: Power Button + Volume Up Button for several seconds
5. Follow the menu at LCD screen to continue the hard reset SONY XPERIA T LT30p

You can choose the step options above to do hard reset while the SONY XPERIA T LT30p get problem or not running well. But we always suggest to do routine backup before your smartphone get problem. If SONY XPERIA T LT30p already stuck or run slowly or not responsive, then better try to do backup as you can because all important applications will be wipe or removed from SONY XPERIA T LT30p after doing master reset, but some data which saved at memory card will be safe, better to remove the microsd memory card before doing the hard reset.

I would pull the battery out for about 10min. If you're not able to remove the battery I would find the reset key sequence to reset the phone.

1. Press and hold both the volume up key and the power
   key for five seconds.
2. After your phone vibrates once, release the keys. The phone restarts automatically

http://www.sonymobile.com/gb/support/faq/xperia-sola/troubleshooting/the-phone-freezes-or-applications-suddenly-shut-down-6/

i did it by turning the phone off. then hold the voliume down button for 5 seconds then when the sony sign poped up keep tapping the back button for 8 seconds.
then just start tapping all buttons exept the power buttions at once for 5 seconds. then hold them all down. not the power button. untill the phone comes on.

How to hard reset the Sony Ericsson Xperia X8First, try this:

1. From the main home screen, tap menu
2. Tap Settings, then Privacy
3. Tap Factory data reset
4. Tap Reset phone
5. Enter your password if required, then tap Erase everything to confirm

If that doesn't work, or if your phone is frozen:

1. Turn the power off. If your Sony Ericsson Xperia X10 is frozen, pull the battery out and reinsert it
2. Hold the Left and right buttons located beneath the display
3. Press and release the Power button
4. Follow the on-screen instructions to hard reset your Xperia X10

All data including third-party applications will be deleted from the Sony Ericsson Xperia X8. Once the wipe is complete, the phone will reboot to its factory fresh state.

how to reset sony ericsson e15i

may i know the frimware of your psp console

Hi there,
Had same problem when loading the latest Touch IT ROM from xda-developers.
Switch Phone Off.
Press and hold the 2 keys on the left and right under the screen, then press the power button.
Blue and white screen displayed. Slide out keyboard,
Press R to continue with Reset or X to Cancel.

you have turn off the psp then take out battery then look at laser then move it to the right and put the game in then go to auto start if on turn off then go to ad hoc mode change channel to 6 reboot it