OK - first of all - don't panic - this will work......
Get yourself a cup of coffee first of all....
OK - now press and hold the Power and Home buttons at the same time for a long time (could be 20 seconds) until the white Apple logo appears - have faith - it will....
Your iPad will reboot - time for another coffee - and all will be well.
You won't lose any apps or anything else - it's not a big deal and we all have to do it occasionally - hey, how many times have you had to reboot your PC!!
Nothing to worry about unless this happens frequently.
Have fun and enjoy your iPad
Tim