Trying to sync my IPad but can't get it to "communicate" with my computer. Keeps telling me "not connecting"

Question

I have been trying to Sync my IPAD to my computer for over an hour, I cannot get it to show that it's "plugged" in.  I keep getting the "not charging" showing in my upper corner.  Is there anything I can do to get it to sync? 
There is nothing wrong with the cable as I just synced my IPHONE and have synced with my IPAD in the past.  I am beyond frustrated.

Answer 1

Let me take up the comment by King Penguin who is right about the charging issue with some computers: not all USB 2 ports are equal apparently.  However, I did read somewhere that even those that are not showing a charging may allow some trickle-charging to occur (take you about 12 hours to notice anything).
However, I think the problem here is that not only is charging not taking place, but the iPad is not shown in the sidebar.  There are usually two possible causes here: the hardware (which in BrookeLeigh's case could be the iPad or its connector) or the software.
In the latter case, no iOS device will probably be shown (IPad, iPhone or iPod touch), which could be what is afflicting tahnehdo.  Nonetheless, before trying some of the fixes Apple suggests, a check with another cable (or computer -- be careful not to sync) might tell you if this is hardware.
If not, Apple KB documents are useful in tracking down and fixing the problem.  Start with this http://www.apple.com/support/iphone/assistant/itunes/ Troubleshooting guide and work your way through. Note there are different processes for Windows and Macs. 
It would be helpful if you could put some more information as even knowledge of the OS will mean a different approach may need to be taken.  We do not know if it is iPad 1 or 2, the OS, the computer you have or if you have other iOS devices that could help you in analysis.