You can create a new user like so.
INSERT [dbo].[Nop_Customer] ([CustomerID], [CustomerGUID], [Email], [Username], [PasswordHash], [SaltKey], [AffiliateID], [BillingAddressID], [ShippingAddressID], [LastPaymentMethodID], [LastAppliedCouponCode], [LanguageID], [CurrencyID], [TaxDisplayTypeID], [IsTaxExempt], [IsAdmin], [IsGuest], [IsForumModerator], [TotalForumPosts], [Signature], [AdminComment], [Active], [Deleted], [RegistrationDate], [TimeZoneID], [AvatarID]) VALUES (37, N'18c4f7dc-2964-41db-9611-8a313bf672d3', N'
[email protected]', N'
[email protected]', N'14F009DDBEF203EDC2124D54FA6D325E16E36D77', N'vw7zHZI=', 0, 0, 0, 0, N'', 7, 1, 1, 0, 1, 0, 1, 0, N'', N'', 1, 0, CAST(0x00009B3600C2192F AS DateTime), N'', 0)
You can this then login with the default details
username:
[email protected]password: admin