The Windows templates with Plesk require some additional steps after the VM is provisioned and booted for first time before Plesk can be used.
Please consult c:\readme.txt in the VM to be sure of the latest version of the instructions, as of this posting it reads -
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To complete the Plesk setup please review and complete the following instructions:
Replace "password" with a unique password in the following commands then run them in your Windows command shell:
net user psaadm "password"
c:\Windows\System32\inetsrv\appcmd set config /section:applicationPools /[name='PleskControlPanel'].processModel.identityType:SpecificUser /[name='PleskControlPanel'].processModel.userName:psaadm /[name='PleskControlPanel'].processModel.password:"password"
Now set the Plesk hostname by replacing the example in the command below:
"C:\Program Files (x86)\Parallels\Plesk\bin\server_pref.exe" -u -hostname host.example.com
The setup should now be completed and you should be able to log in with the following:
http://localhost:8880
Username admin
Password: pass123
Important - please log in and change your Plesk admin password immediately.