Charges from Apple charger but not computer
I have an iPhone 3GS to fix that will charge from the Apple charger but when plugged into a pc it won't charge and shows up as an unknown device that may have malfunctioned. Also when it is plugged into the Apple charger it gets power but doesn't seem to store the charge as it runs out of power quickly as soon as it has been unplugged. Also I have tried cleaning the dock connector but it hasn't fixed it.
Does anyone have any idea what is the problem here?