When I click inside the Parallels window the mouse cursor disappears. At that point I have neither Mac or PC mouse working. I have not yet been able to install Windows OS but that is another isssue.
When you click inside the console window, the OS running in the virtual machine is responsible for displaying the cursor. If you have no running OS, you won't have a mouse cursor either. To get it back, hit Coltrol and Option (which is Alt, as well, to the guest OS) at the same time, then release.