lock button not working

[Hina Nadeem]

I am trying to lock up my phone using a pattern or a pin but neither seems to work. my phone wont lock?? please help me on this one!!

 

[AndyOpie150]

If it is a STOCK phone, never having been rooted then try:
1. Pull battery and hold down the power button for 30 sec.
2. If the above didn't work then download App Tyrant from the market. Open it up and let it do it's thing. Unmount SD card and pull it. Put it into a computer and transfer all data to a folder (you can make a new one). Put the SD card back in the phone (it should auto mount, if not mount it). Now go to the menu/settings/privacy/factory reset. This will wipe all user data off the phone and return it to a fresh out of the box state.
You should now be able to set up a screen lock.
Your SD card should be OK. If not, choose the erase SD card option in the storage setting, then transfer all the data you saved onto the computer back to the SD card. Using a file manager like ES File explorer, open up the AppTyrant folder on the SD card (might be named Root Uninstall as well). Copy and paste all apks to the root of the SD card (root of the sd card is just not in any folder, but the same directory level as all the folders: /sdcard. Now tap each on and install. This will get all your apps installed quicker then having to track them down on the PlayStore.