Solving the problem "Class not registered" in Windows 7

There are several of the most common situations when the "Class not registered" notification appears on the screen when using Windows 7, and it belongs to them: starting one of the browsers, an attempt to open a picture, interacting with the Start button or taskbar. For each of them there is a variant of the correction of the problem, and the proposed solutions are not interchangeable - it is necessary to select a method based on the cause (except for option 4).

Option 1: Installing the default browser

If the "Class not registered" problem appears when you try to start a specific web browser, most likely, the default settings for it were discarded or not exhibited at all.

1. Open the "Start" and go to the "Control Panel" menu.



2. Here, find the category "Default Programs".



3. In the menu that opens, click on the first clickable inscription "Set the default programs".



4. Among the list in the left menu, find the desired browser and click on it with LKM.



5. In the on the right panel, specify "Use this default program".



6. If you go to "Select defaults for this program", you can immediately specify what formats will automatically run through this web browser. You need to configure this parameter only if the problem appears precisely when you try to open specific files through the browser, and not at its regular startup.

Approximately the same way is carried out by installing any default browser, but there are other options for performing this task. You will find more detailed instructions on our implementation in a separate article on our website by clicking on the link below.

Read more: Select the default browser in Windows

Option 2: Configuring Associations for Images

Reset the parameters of file formats associations for image viewers - the second popular reason for the notification of the "Class notification" in the Windows 7 operating system. The solution in this case will be about the same as for web browsers.

1. In the main menu of the Control Panel, select "Default Programs".



2. Go to the Default Program Specifications section.



3. Select the desired photo viewer and assign it the main one.



4. Additionally, go to the "Select defaults for this program" menu and check all the items present there, then click on "Save".

In most cases, these actions are enough to establish the correct viewing of images in Windows 7, but sometimes the data of manipulation does not lead to the positive effect of the correction of associations. Then you have to manually edit the registry parameters or use the radical methods, which in the detailed form read in the article below.

Read more: Troubleshooting images with opening images in Windows 7

Option 3: System DLL Registration

Failures in the operation of system DLL files - the situation with which the ordinary user faces extremely rarely. However, it is this that can serve as a problem when you try to interact with the Start menu or taskbar. Then all the necessary DLLs must be re-registered through the command line, which will not take much time.

1. Run the console on behalf of the administrator. If this fails to do through the "Start", use alternative methods, we are talking about the reference below.

   Read more: Call "Command Line" in Windows 7



2. Copy the following contents and insert it entirely into the "Command Line". Activation of all commands will occur automatically, and you can only wait for the completion of the operation.

   

   regsvr32 quartz.dll

   REGSVR32 QDV.DLL

   REGSVR32 WMPASF.DLL

   regsvr32 acelpdec.ax.

   regsvr32 qcap.dll

   REGSVR32 PSISRNDR.AX.

   REGSVR32 QDVD.DLL

   REGSVR32 G711CODC.AX.

   REGSVR32 IAC25_32.AX.

   REGSVR32 IR50_32.DLL

   REGSVR32 IVFSRC.AX.

   REGSVR32 MSSCDS32.AX.

   regsvr32 l3codecx.ax.

   REGSVR32 MPG2SPLT.AX.

   REGSVR32 MPEG2DATA.AX.

   REGSVR32 SBE.DLL

   REGSVR32 QEDIT.DLL

   regsvr32 wmmfilt.dll

   regsvr32 vbisurf.ax.

   REGSVR32 WIASF.AX.

   REGSVR32 MSADDS.AX.

   REGSVR32 WMV8DS32.AX.

   REGSVR32 WMVDS32.AX.

   REGSVR32 QASF.DLL

   regsvr32 wstdecod.dll

3. A number of notifications will appear on the screen with the successful registration of DLL libraries.

After that restart the PC and try to click on "Start" or control the taskbar again. If the error still appears, it is possible to solve it by scanning system files to integrity, as read in the article below.

Read more: Check the integrity of system files in Windows 7

Option 4: Verify local computer services

There are a number of local computer services that are directly related to associations of files, and failures in their work can affect the appearance of the problem under consideration. Automatic service checks - a universal method that can help in each situation, and it can be realized like this:

1. Open the "Run" utility via the Win + R keys, and then enter DCOMCNFG in the field and click on ENTER.



2. In the menu that opens, follow the path "Component Services" - "Computers" - "My Computer".



3. Open the DCOM configuration directory.



4. File checking will be made by the system, and if any services are functioning incorrectly or not yet installed, their correction will occur in automatic mode, and you will only have to confirm the addition and expect the end of the operation.