I'm sorry about the issue. Was it working previously?
What's the model of your kindle?
Are you trying to transfer Kindle books from the PC to the Kindle device?
Do you have windows xp, vista, or 7, or 8?
What is the model of your Internet modem/router device, if any?
If you have a USB flash drive or an external USB hard drive, does it work on the PC?
Please reply at the box below. Thank you.