The error code 651 is most commonly encountered in Windows 8 and Windows 8.1, and affects desktops and tablets.
Error 651 is displayed when users try to connect their PC to the Internet using a modem.
Modems have proven to be inefficient in today’s age of high-speed broadband internet, but users still use them because of the high internet speeds they offer.
Modems use telephone lines to connect to the Internet, making them slower than cable modems and DSL connections.
The error 651 displays an error message that says:
> The modem or connecting software is not installed. Please install the modem > software.
This can be problematic as users can’t use the internet.
- Error 651 occurs when Windows is unable to recognize a modem.
- The solution is to update the modem driver or check your Internet connection.
PC problems? Solve them in minutes.
Run the SFC and DISM scan
- Press Windows Key + R, type cmd, right-click on Command prompt, and select Run as Administrator.
- In the Command prompt, type the following command and press Enter: DISM /Online /Cleanup-Image /RestoreHealth
- If the above command doesn’t return any results, try running SFC scan.
- If the SFC scan doesn’t return any results, type the following command and press Enter: DISM /Online /Cleanup-Image /RestoreHealth /ScanHealth
Check if your modem is compatible
- Usually, the error 651 appears when you attempt to upgrade your OS from Windows 7 to 10.
- To check if your modem is compatible or not, visit the official Microsoft website. Click on the Get updates button and then check if you have the latest driver for your device.
- Also check if you have the latest firmware installed.
- Download the compatible driver and firmware for your device.
- Uninstall your old modem driver and firmware.
- Download the new driver and firmware.
- Install the downloaded files and check for any improvements.
Reinstall the modem driver
- Press the Windows key + X and choose Device Manager from the list.
- Locate Modems and right-click it.
- Choose Uninstall device from the menu.
- Now, click Uninstall in the confirmation dialog.
- When the process is finished, restart your PC and try to connect again.
Reconnect the modem
- Press the Windows Key + S and type Internet Options.
- Select Internet Options from the list.
- Go to the Connections tab and right-click on your modem.
- Select Properties.
- From the Windows Security window, go to Local Policies > User Rights Assignment.
- Open your modem’s Properties (right-click it and select Properties).
- Navigate to the Security tab > check the box for Enable this connection.
- Click OK to save the changes.