Now, we're going to check your ethernet card. Open the device manager by going to Start > Control Panel > System. Look for the panel that says hardware, and then click the button that says "Device Manager." Now, in the list that comes up, you'll want to look for Network Devices. If there is an X by your card, you likely have accidentally disabled the card. Right click it, and click "Properties." Select "Enable this Device", click apply, and OK. If there is a yellow box, you need drivers. You'll have to use the disc that came with your system (or the card if you are not using an integrated system card), or download the drivers from the manufacturer, from another computer with an Internet connection.
If you need to download the drivers from another computer, you should use a flash drive, an external hard drive, or some other form of transferable media (CD, floppy disc) to get the files, so that you can transfer them back to your computer. When you visit the manufacturer's site, be sure to save the files to that drive (look in My Computer to find out what drive letter your flash drive or external has been assigned); or you can save them to the "My Documents" folder and burn them to a CD. When you have saved the files, go back to your computer and insert your flash drive, or whatever medium you used to save the files. Look for the file name you downloaded on to it, and double click it. This will allow it to run and install on to your computer.
If you still cannot get the drivers to install, you can try the "Add Hardware" option in the Control Panel, which will automatically search for hardware installed in your computer that does not have active drivers. Point the computer to look in the location where you have stored the driver files, and it should find them on its own.
Once you have done these things, check your Internet connection again by repeating the ping step from step one.
If this does not work, you'll need to contact customer service for your Internet service provider to see if there are any outages in your area. If you are using a leased modem, they will also be able to help you determine if the modem has gone bad.