When you install a VM of Windows 2003 SP1 / SP1 Operating System, in Hyper-V and you try to login and click with your mouse, it says with a error message "Mouse Input not captured". and Your need of-course Google and get a great idea that you need to install Integration Services from the following path of your running VM’s window,
Click Action > Insert Integration Services Setup Disk.
After the message in bottom or a popup, reboot your system. Then you will be able to use mouse inside the VM properly.
Well for this, you need at least a SP2 on your operating system, mean on Windows Server 2003. Mostly, Professionals says, OK, no problem, let me to play with keyboard but when they try to run network, there is no network access as below image shows.
For Network Access, you need to shut down your VM and have to add "Legacy Network Adaptor" as below image,
After this, your Mouse will be working on Hyper-V Guest VM and also you may notice that there are two Network Cards are available now. You may un-install your "Legacy Network Adaptor" but that need to shut down your VM. After, finishing above setup. You have a normal running VM. Hope this article will be helpful for you.