I don't know what you've already tried, so I just can guess that you wanted to turn on your iPad, and it didn't work.
Here are a few things you could do as well:
Reset your iPad. To do this, press and hold Home and Power button at the same time until the Apple logo appears, release both and let the iPad power up on it's own.
Make sure it has enough charge to turn on.
Restore it using iTunes on your computer: http://support.apple.com/kb/HT1414