Have you tried restarting your iPad?
If that doesn't work,hold the on/off button and the home button until the apple logo appears. If this doesn't work,take it to the apple store and let them take a look at it. You may have a defective screen,requiring replacement of the iPad.
How long ago did you purchase your iPad? iPads come with 90 days of free telephone technical support. Here's how to contact Apple. It gives the US phone numbers and a link to the worldwide phone numbers.
If you purchased the AppleCare plan for your iPad the free telephone support is extended to the length of the AppleCare term.
I have exactly the same problem suddenly happening with no cause. 2 year old 3g iPad 16GB - any further news ?
Wow, was this caused by any external damage? I hope you've contacted apple directly
The OP stated in another thread that the problem started as the result of a dropped iPad. He hasn't come back to give us any updates.
Here is the other thread.