Hi IzabelaM, after the release of Parallels Desktop 11 for Mac, we have stopped proving trial for Parallels Desktop 10 and older version. You can try purchasing Parallels Desktop from re-sellers like Amazon, Apple Store etc.
Hi ChanceU, the issue that you have reported seems to be a known issue and our Engineering team is ready working on this. You can try deleting the virtual machine and adding the Boot Camp partition once again and check how it goes.
Hi Kieran, yes you will have to get the full version of Parallels Desktop 11 for Mac. Un-installing and re-install Parallels Desktop will not affect your virtual machine, so the Windows 7 virtual machine is safe.
Hi @anjag, please try to download the Windows 10 .iso file from this link: https://www.microsoft.com/en-in/software-download/windows10
And then follow the steps suggested here to install Windows.