I turned on my iPad, (yes it is fully charged).
It is requesting sync for Itunes.
I can't get past that.
It does not recognize any clicks/taps.
Only the anti rotation switch works.

What do I do?

Contact apple care or take it to an apple store.

Sorry, it might sound obvious, but is the iPad connected to a computer running iTunes?

Ummmmm, if it is requesting you connect to iTunes have you thought about connecting it to iTunes?

I think the best suggestion for this site is to try not to be sarcastic when posting. People are really looking for answers and need help. Similarly, I plug my ipad (fully charged) into my computer, pull up itunes and wait for the screen on my computer to change to a "register your ipad" like the instructions say it will and nothing happens. I have checked all software updates and I have all new software. I have tried multiple apple power chords and both USB ports on my MacBook. Please respond if you have experienced this or if you know how to remedy. Thanks so much.

I had the same thing after upgrading to 4.2.1
The iPAD refused to see the iTune - or maybe the other way around.
After a all night of "googling" the internet, I gave up.
Took my iPAD to work.
Connected it to my LAP top there (haven't got it at home that time) .
It immediately responded and started working iPAD-iTune "hagging" each other.

Bottom line. Something went wrong on my iTune Application at home.
So , my 1st advice is try connecting to another PC.
2nd advice if you don't have access to another PC, try uninstall and re-Install iTune.