There are three ways to change the default PDF opening method to your desired application: through File Explorer, System Settings, or Control Panel. First, you can right-click on any PDF file and select "Open with" and check "Always use this app"; secondly, enter the "Default Application" setting through [Win I] and specify a program for .pdf; you can also manually associate it through the "Default Program" function of the control panel. If it is still changed after setting it, you need to check whether the security software has reset the association, and make sure that the PDF reader's own settings have been set to default to avoid conflicts between multiple PDF software and lead to unstable association.

Windows 10 right-click menu can be managed through third-party tools, registry editing, or command line. Firstly, it is recommended to use visual tools such as "Windows Right-click Menu Management Assistant" to add or delete menu items after running as an administrator; secondly, you can manually edit the registry, create a new shell item under the relevant path of HKEY_CLASSES_ROOT and set the command subkey to point to the target program. You need to back up the registry before operation; finally, you can use the open source tool ContextMenuManager to batch manage menu items through command line list, disable, enable and other parameters, which is suitable for advanced users.

Windows 11 can enable the taskbar clock to display seconds through settings, registry, command line, or third-party tools. 1. Turn it on in settings: Go to Personalization → Taskbar → Taskbar Behavior and turn on "Show seconds in system tray clock"; 2. Registry modification: Create a new DWORD value ShowSecondsInSystemClock under HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced and set it to 1; 3. Command line execution: Run PowerShell as an administrator and enter regaddHKCU\Softw

1. You can view and adjust Windows 8 background services by running services.msc, Task Manager, Computer Management and Command Prompt. The operations are applicable to quick access, resource monitoring, comprehensive configuration and batch query scenarios.

First, use the DISM command to install .NET Framework 3.5 from local sources. If it fails, enable the function through the control panel, then repair the system files and reset the update service, check the group policy settings, and finally use third-party tools to assist in the repair.

First, use Windows built-in tools or third-party software to back up the Win8 system to a mobile hard drive. Specific steps: Connect the mobile hard disk, enter "Backup and Restore" through the control panel, select "Create System Image" and specify the mobile hard disk as the storage location, confirm the backup content and start creating; or download third-party software such as EaseUS Disk Copy Tool, select system clone or disk mode, copy the source system disk to the target mobile hard disk, ensure sufficient capacity, perform the cloning operation after confirmation, and keep the device connection stable until completion.

Screen tearing is caused by the graphics card frame rate being out of sync with the monitor refresh rate, which can be solved by enabling windowed optimization, turning off full-screen optimization, setting vertical sync, calibrating the refresh rate, and turning off automatic HDR.

The disappearance of the recycle bin icon can be restored by three methods: first, turn on the desktop icon display in the personalization settings; second, use the registry editor to modify or create the corresponding CLSID key value; finally, the administrator can run the sfc/scannow command to repair the system file, and the icon can be restored after restarting.