phone cant charge while using tvout

[johnq]

idont know what the wrong with this phone icant keep this phone chargeing and playing movie at the same time iused to do that with 6800 and 6900 .. and ihave option under main battery .when device is turned on ,do not charge the battery when connected to the pc , idid not mark it at all ijust left it as is ...,when i connect my pc it say charging but just cant charge to full on even a little , ,
iwas watching movie today on www.joost.com and after hours and half my phone shut down ipalged the phone to charge while watching but it wont accept any charge when ibrowese the internet . or runing any games
itryed to serch for sultion befor ipost this .. ifound nothing ...
ineed your help guys
thanks