If you are sure it has been charged, but now the charge light will not come on when plugged in, and the tablet will not power on, hold down the Home/Windows Button (On the left side under the Volume Button) and the Power Button for 15 Seconds. This will force the unit to reboot. Once it boots, Google "Laptop Battery Monitoring Tool" and use the tool to check the life of the battery. Some of them you can also plug the charger in, and it will tell you the charge rate, then you will know if the Charger/USB cable is bad.
[http://batteryeater.com/download.html?downloadfile=release/beProv270.zip|Battery Eater Monitoring Tool - Download] (I use this one mostly, it has more information)
If you are sure it has been charged, but now the charge light will not come on when plugged in, and the tablet will not power on, hold down the Home/Windows Button (On the left side under the Volume Button) and the Power Button for 15 Seconds. This will force the unit to reboot. Once it boots, Google "Laptop Battery Monitoring Tool" and use the tool to check the life of the battery. Some of them you can also plug the charger in, and it will tell you the charge rate, then you will know if the Charger/USB cable is bad.
Two of the better ones are :
[http://batteryeater.com/download.html?downloadfile=release/beProv270.zip|Battery Eater Monitoring Tool - Download]
and
[http://dw.cbsi.com/redir?ttag=direct_download_now_link_click&lop=link&ptid=3000&pagetype=product_detail&asid=13716847&astid=2&edid=3&siteid=4&destUrl=http%3A%2F%2Fdownload.cnet.com%2FBATExpert%2F3001-20430_4-76080937.html%3FhasJs%3Dn%26hlndr%3D1%26dlm%3D0&onid=20430&oid=3000-20430_4-76080937&rsid=cbsidownloadcomsite&sl=en&sc=us&pdguid=download%3A13716847&topicguid=utilities%2Fbattery&topicbrcrm=windows%20software&pid=13716847&mfgid=67841&merid=67841&ctype=DM&cval=NONE<ype=dl_dlnow&spi=0aa96e6d260efe15e1340f4a4ad133d4&devicetype=desktop&pguid=72fbf0b3fe2fa087216a4483&viewguid=OsXJpoUASH-KbCRTBMbVwwizH33k-kamQHCy|BatEXPERT Monitoring Tool - Download]