This answer is from this link:
4 Simple steps. Set Date, Clear Play Store, Clear Google Framework, Reboot.
If nothing works, try removing your Google account, then signing in again.
Settings ---> Google ---> Tap on your email address ---> Tap on the three dots at the top-right corner ---> Tap on "Remove account".
Check out this too.
From the home screen, hit the menu button, and go to settings. Next go to applications, and then manage applications and click on the all tab at the top. Scroll down to Market and clear your data and cache. Once you open Android Market, you’ll be prompted to accept the new terms and conditions of Google Play and then the app will update itself.
Download the APK from the Google Play Store, which was provided on Android-centric blog Droid-life. You can download the APK from MediaFire. Installing the APK would replace the Android Market app.
Again another link
- Turn off the device.
- Press and hold the Volume Up key, Home key, and Power key at the same time.
- When the phone vibrates, let go of the buttons.
- When the Android System Recovery screen appears, let go of the Volume Up and Home keys.
- Press the Volume Down key to move to and highlight wipe cache partition.
- Press the Power key to select and wipe the cache partition.
- After the wipe is finished, go back up till reboot system now is highlighted and press the Power key to restart the phone.
Some video tutorials:
- http://www.youtube.com/watch?v=VDc-JwbauAM
- http://www.youtube.com/watch?v=tRO3VAITias
- http://www.tech-recipes.com/rx/29473/ok-android-jelly-bean-reset-app-preferences/
Hope it helps you.
As said by @CodeMonkeyAlx
You can Factory reset it but if you have important data on your device then be sure to have a Backup . Here i have listed out some Backup apps. Some needs rooted device whereas some works for unrooted device too.