Windows Error 721

Windows Error 721 is a frequently occurring Windows problem that seems to be especially common among HP devices running on XP Windows versions.  The error usually occurs when you try to establish a VPN or access the Internet using your modem. When the error arises, it will usually prevent you from connecting to the Internet or connecting to a remote computer.  This error is mainly caused by an outdated or incompatible modem device connected with your HP computer.  You need to resolve the issues surrounding your HP machine to be able to remove the errors and connect to the Internet again.  This tutorial will help you fix Windows error 721 quickly and easily.

What Causes Error 721?

Error 721 is most likely caused by outdated HP drivers, problematic programs that make use of the modem to connect to the Internet, or errors inside a crucial database known as the registry.  Basically, whatever the cause of the problem, it renders Windows unable to properly access and read a file or setting it needs, and it is this what prevents a successful connection to the Internet.  You need to identify the source of the problem to be able to fix it – follow these steps to learn how:

How To Fix Error 721

Step 1 – Update Any HP Drivers On Your PC

The problem could be caused by outdated HP drivers on your PC, so you need to update the HP drivers you have installed. In most cases, this will fix the problem and make the error go away  Here’s how you can do this:

  • Click Start > Control Panel > System > Hardware, and click the Device Manager button.
  • Inside the Device Manager window, locate the modem device driver, right-click on it and select “Update Driver Software
  • Follow the update wizard
  • Restart your PC

Step 2 – Re-Install Any Programs Causing The Error

If not the drivers, then it may be that faulty program files are causing Windows to generate the error message. To resolve the problem, you can re-install any programs that you think are linked to the error.  To start re-installing, you need to remove the application first and follow the steps listed below:

  • Click Start
  • Select Control Panel
  • Choose  Add/Remove Programs and select the program from the list
  • Uninstall the application by clicking the “Remove” button and wait for the removal process to be finished
  • Restart your PC

To re-install the program, run the installation command either by using a CD installer or locating it within your hard drive.  This process will likely replace erroneous program files and will prevent the error notification from showing.  However, if the problem is still present, proceed to the next step.


Step 3 – Clean Out The Registry Of Windows

As mentioned earlier, the registry is a crucial database in your computer.  It serves as a central storage depot for all of the options and settings of the programs and files installed on the PC.  Each time Windows loads a file or program, it accesses the registry to retrieve the required settings it needs to setup the program. The only problem is, the registry is rather susceptible to getting damaged, and its settings often become corrupted or are misplaced by the system, meaning Windows cannot read them anymore. Cleaning out the registry can fix the annoying Windows error 721, which you can accomplish by using a reliable ‘registry cleaner’ that can perform a thorough registry scan and repair detected errors inside.

We highly recommend that you download and install this tool to get rid of 99% of system errors as it has been found to be consistent in restoring the health of your PC.