None of the keys on my blackberry curve work . i can scroll using the tracking ball , but other then that nothing works .

Try to reinstall your blackberry software since unlocked blackberry curve software usually has previous network configuration. But to make sure what exactly your problem you can bring your phone at local mobile repair shop and asking them to check your phone.

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