It sounds like the laptop may have been previously used or improperly reset before it was sold to your friend. When a device is reset, it should return to a state similar to the Out of Box Experience (OOBE), which typically does not retain any previous user's information. If another email address is appearing on the Microsoft Account login screen, it suggests that the device may not have been fully cleared of previous user data.
In this case, it would be advisable to contact the retailer to report the issue, as it could indicate that the laptop was mis-sold or not properly refurbished. They may offer a solution, such as a replacement or refund, especially if the device is not functioning as expected due to this issue.