Alissa, when you say you have followed the advice on the Apple website, does that mean you have worked through all the tips in this knowledgebase article?
Have you tried connecting the USB end of the cable, start iTunes, and while holding the home button on the iPad connect the 30-pin connector to the iPad?
Addressing this issue:
And when we charge the ipad we use the same cable on a socket in the wall,which works, but charging with the pc doesn't work either.
The fastest way to charge your iPad is with the included 10W USB Power Adapter. iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter. When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge, but only when it's in sleep mode. Make sure your computer is on while charging iPad via USB. If iPad is connected to a computer that’s turned off or is in sleep or standby mode, the iPad battery will continue to drain.
Yes i basicly tried everything in the article, when I tried something and it didn't work I klicked on the next option, so I'm pretty sure that everything possible, but it just doenst do anything. At one point I had high hopes when I tried the following http://support.apple.com/kb/ht4097?viewlocale=nl_NL I did get the screen as shown on the ipad, but not the message.
I just don't know what to do, I thought that the Ipad might be broke, but as I said before when I charge it with the power adapter it works normal.
Will have to do some searching, but there was a posting by b noir a couple months ago about ways to get MS Windows to "see" the iPad...I will see if I can find that again.
If there is an Apple store/genius bar handy it might be good to stop in and have them take a look, probably not the iPad that is having the problem but they might be able to do something to help.
Meanwhile, will see what I can dig up out of the recesses of the brain.
Still annot find the discussion by b noir, but there are several discussions about removing iTunes (uninstall) per this knowledge base article, and then reinstalling iTunes. iTunes then recognizes the iPad. Note that the article is for Windows XP but sould be very similar for other flavors of Windows. the important point the posters said is to make sure all apple-related pieces are removed in the uninstall so you are clean for the reinstall.