If you are using a dial up modem then you may be familiar with the 663 modem error. This is a common error seen by people using dial up connections. This error may appear on your screen when trying to connect to the internet. It is telling you specifically that 'the media.ini file refers to an unknown device type' and this usually means that one of the network configuration files contains information that is not valid. So in other words, the computer is telling you it does not recognize your modem and does not know how to use it.

There are several reasons that could cause this type of error, but the most obvious cause would be if you have installed a new modem lately and your system is not able to communicate with it properly. To fix this, the first thing you need to do is make sure the correct modem is selected in the Dial-Up Networking Connection box. If you have had other modems previously installed on your PC, it may be trying to access them instead of the new one. You just simply need to tell the computer to start using this new modem now.

You may have to scroll through the drop-down list to find your current modem if others are listed there. As new devices are installed on your system, the PC will still keep the software for them even though the device has been replaced. This may be a little confusing in cases where you have replaced hardware, but if you actually had two printers, or two types of network connections that you use, you would need to the PC to keep all the configuration files for them on hand. In the Dial-Up Networking Connection box, make your current modem the default and try connecting again. If this fixes the problem, you should consider uninstalling any old modems from your system to avoid having this happen again.

However, if you only have the one modem showing up and it is the correct one, you can try to uninstall your modem and reinstall it again. Believe it or not, this process fixes many hardware related issues, just as rebooting your PC can fix many ailments as well. Sometimes, even if you have not installed any new hardware, you may have to reinstall it to resolve other similar problems.

Make sure you have the correct drivers for your modem before continuing. If it is a new modem, you should have a disk that came with it. You can also try looking on the manufacturer's website for the correct drivers and software for your type of equipment. Follow the steps below:

1. Double-click on the “My Computer" icon on your desktop.
2. Then from there double-click on the "Control Panel" icon.
3. Now double-click on the "Modems" icon.
4. Under the "General" tab, you should see your modem listed. It would be a good idea to write down any information such as the manufacturer and model number etc. before continuing.
5. Highlight the modem that you are planning to uninstall and click "Remove".
6. Close the window and reboot the computer (if you are not prompted to reboot).
7. In most cases when the PC starts up again Windows will notice the new modem and reinstall it for you.
8. When you get back to your desktop, go back to the "Modems" icon in the "Control Panel". If the modem was not installed you will be prompted with a "Hardware Setup Wizard".
9. At this point, you will need the correct drivers for your modem. If you have a disk, you will need to insert it and choose the correct drive. If you have downloaded the driver from the internet, you will need to select the folder where you have saved it.

Reinstalling the modem will fix the 633 error most of the time. If this does not fix your problem, then you will have to check with the vendor or the manufacturer of the modem. It is still most likely a software-related issue, but it is going to require more in-depth troubleshooting and may even indicate a problem with your operating system. The problem could be that the modem driver you are using is not compatible with your system, in which case, the manufacturer can help assessing which driver would be the best for you to use. Many hardware manufacturers have 1-800 numbers and tech support on their websites that may also be able to help you resolve this problem.