Hello there Vicky8,
Thank you for using Apple Support Communities!
I would recommend this troubleshooting from the article named iPhone: Hardware troubleshooting found here http://support.apple.com/kb/TS2802
Important: Only original iPhone can be charged from a FireWire-based power source. If iPhone is connected to a computer that's turned off or is in sleep or standby mode, the battery may drain.
- Verify that the outlet being used is working.
- Try another USB power adapter if available.
- If no other USB power adapter is available, try connecting to a high-power USB 2.0 port (not a keyboard). The computer must be turned on and not in sleep or standby mode.
- Try another USB cable if available.
There was a step 5, which pointed to the article you came from already, so I left that off.
All the very best,