Go to Start/Run and type devmgmt.msc and press enter. In the Device Manager expand Network Adapters. Are there any devices with yellow flags? If so, these devices need drivers installed.
What is the make and model# of your computer/motherboard?
On an internet computer, Go to the Manufacturers Support/Download Drivers site. type in your make and model# or Service Tag # and then choose your OS version (eg) Windows XP, then download the Network Adapter (LAN) driver for your model. Save the driver to a USB Flash drive, along with any other drivers you may need from the Device Manager and install it on the troubled computer.