Mark has a Windows machine and he took Leo's advice and created a limited user account out of his admin account. But he lost his original information as a result. Leo says the trick is to create a separate admin account first, then modify the existing account as a limited user. But he can't even see the original account.
The chatroom says to try rebooting his system into Safe Mode. Then he should look for the account. It could be hidden and going into safe mode will enable him to find it.