A: Check the original purchase email. If lost, contact Visual SVN sales with your order number or company name. They can resend it.
Some overzealous AVs lock the registry keys. Add C:\Program Files\VisualSVN Server\ and the registry path to your AV exclusions. visual svn server license key fix
If you need a step-by-step fix, follow the sections below. A: Check the original purchase email