In 2010, you came across a site that was giving away bitcoins. The site said it was free money so you signed up. You were logging in to figure out how it was money but couldn't. The last time you logged in you had more than 100 bitcoins. Later you forgot about the site until 2017 when a ponzi was advertising Bitcoin. Bitcoin? The name rang a bell and you stated hearing stories. You remembered you must have many bitcoins somewhere but you can't even remember the name of the site. How would you recover your BTC?
It's quite difficult to solve this kind of problem as it's a matter of memory loss while losing your bitcoins that worth's almost a million dollar base on the current price but more than a million dollars last 2017.
If I were in this kind of scenario, I will do everything to recover it. First, I will check whether the computer that I use is still there and dig up it's history in case it is still there. Or I will hire some tech addict to do the digging and will give a huge reward if they can recover it.