My buttons wont work on my blackberry curve i can scroll but none of the buttons work. i have tried to reset it and back it up on the desktop but the problem still persists. My convience buttons just stopped working. When I go through the options menu and try and click on screen/keyboard it does not do anything. All other options on the options menu will work but this one. Very wierd.

There are few videos out there for the buy this is the one that works.
The introduction of this video is long,please skip to 3:00 on the video to get started.

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The official instruction from BlackBerry
On the BlackBerry device, the following error message appears after pressing the Mute button, accessing an application, or performing a hard reset:
523 app. error. Reset.


Resolution

To resolve this issue, complete the following steps:

1. Upgrade to the latest version of BlackBerry Desktop Software.
2. Remove any recently installed applications on the BlackBerry device, then install the latest version of BlackBerry Device Software on the BlackBerry device. For more information about how to upgrade BlackBerry Device Software, see KB03901.

Perform a hard reset on the BlackBerry smartphone.
"Remove the battery and sim when mobile is turned on - Re-insert battery and sim and check "
Still if you have same issue Install Blackberry Device Software.

1.Connect the BlackBerry smartphone to the computer and open
BlackBerry Desktop Manager application
2. Double-click Application Loader.
3. Click Next to start the installation process.
4. Type your BlackBerry smartphone password, if prompted, and click
OK.
5. Select the check boxes next to the names of the applications you want
to load, and then click Next
6. Click Advanced, and then select the check boxes beside Erase all
application data and Erase all currently installed applications
7. Click Next.
8. Click Next > Finish.
9. When the process is completed, the message, The loading operation was successful will appear. Click Close to return to BlackBerry Desktop Manager.

I Hope this information wil fix this issue

You will need to get your blackberry repaired if your in the uk send me an email you can contact your provider if on a contract

try to do a master reset

i would recommend reloading the device software using the desktop software available on blackberry.com
normally a blackberry will not tell you to enter 'blackberry' unless it is trying to wipe the device.

I had a similar problem, and the only solution is to change the trackball which cost between $5 & $10 dollars on e-bay. An easy and cheap fix, it comes with the tool to replace the assembly. A kid can do the job

Have you had any water damage? I guess the phone needs to be opened and you need to look at actual connections on the board especially under the keypad membrane. You can find opening instructions on the 8300 by a google search on many sites

There is a program called "JL_Cmder". Its a Program which can Wipe or reset your phone when your phone is connected to the computervia the USb cable.

You phone could just need a simple reset if the problem is based upon the software.
To do that click the link below to download the Blackberry Desktop Manager and the Blackberry Device Software for your Curve and run the app loader to reset your device
https://www.blackberry.com/Downloads/entry.do?code=577BCC914F9E55D5E4E4F82F9F00E7D4

You will need to use the Desktop Manager in order to do this. You can download it from here:

http://na.blackberry.com/eng/services/desktop/

Once installed, do the following (instructions are based off of 4.6 version of Desktop Manager):

1. Connect your BlackBerry to your computer via USB and open the Desktop Manager.
2. Open the Backup and Restore section.
3. Click on the Advanced button in the Advanced section.On the left-hand side the list of the device databases will show.
4. Scroll down and select Address Book.
5. Click the Clear button.

This will clear all contacts off the BlackBerry.