My iPad is not starting

Assuming that the battery isn't empty (and it can take up to 15 minutes of charging before it will respond), then have you tried a soft-reset ? Press and hold both the sleep and home buttons for about 10 to 15 seconds, after which the Apple logo should appear - you won't lose any content, it's the iPad equivalent of a reboot.

Start by making sure you are charging it correctly. If are using the charger that came with it, be sure it is charging when you plug it in. If not, try a different iPad charger and cable. Be sure it is a 10w or 12w charger, not an iPod or iPhone charger. the iPad needs more power. You can also read about charging here:

http://support.apple.com/kb/ht4060