Lizelle, yes this is possible
if you sent that person an email through Cvent (most commonly an email invitation).
If you did that, you can run a Standard report called "No Responses and Visited" (Event --> Reporting --> Standard Reports) that will show you the name of the invitee and their details. There is a column for their status. If it says "visited," it means they visited the site but didn't register.
As a reminder, the Invitation Reminder email that you can send from Cvent automatically includes anyone in "visited" status, but it's also possible to create a custom reminder that you can send just to people who visited.