Try a program from Asus, AI Charger
http://event.asus.com/mb/2010/ai_charger/ .
I installed it on my Dell precision 4600 laptop (AFAIK not an Asus motherboard) which would not charge the iPad 2 previosly and it works great now. Even charges my new 3rd generation iPad. It seems to say it is changing the registry (Windows 7) but I did not realize that ahead of time so I don't know what key it changes.