Hi'
- Draw a wrong pattern for 5 times.
- Wait 30 seconds
- Touch "FORGOT PATTERN".
- Enter your Gmail account login details.
- This is the account that you used when you activate google play store service
This will reset your screen lock to default.
Make sure you have at least 5MB internet data connection before you do this.
If You never linked your tab with your google account you will then have to hard reset your tab.