Hello,
Thank you for posting in Q&A forum.
We suggest that you check the following points to solve the problem of not being able to use the mouse within the 2003 version virtual machine:
Mouse Integration Service: Ensure that the latest version of Hyper-V Integration Service is installed in the 2003 version of the virtual machine. These services help provide a better virtualization experience, including mouse support.
Virtual Machine Settings: Check the settings of the virtual machine in Hyper-V Manager to ensure that the mouse integration feature is enabled. This can usually be found in the integration services section of virtual machine settings.
Mouse driver: Ensure that the mouse driver is correctly installed and working properly in the 2003 version of the virtual machine. Sometimes it may be necessary to manually install or update mouse drivers.
Virtual machine connection method: Try changing the connection method of the virtual machine, such as using RDP connection or other remote connection methods, to see if the mouse can be used normally.
Hope this answer can help you well.
Best regards,
Jill Zhou