One day while you are attempting to log in to your Facebook account you were flag with a message saying Incorrect Email/Password Combination. Have you tried using Forgot password feature from Facebook reset link? Go to http://www.facebook.com/reset.php to give it a try. If Facebook didn’t send you any new email regarding reset password and you already exhausted your memory of the entire list of passwords you know and still to no avail. It is possible that your account has been hacked by someone.
I suggest that you visit here to view all the topics on how to restore your Facebook account, Phished account, Money transfer scam. In this page you can also find more links concerning Protecting account security, Tips for keeping your account secure, How Facebook protects your information, Suspicious emails and notifications, Editing your Privacy Settings, Approved Devices, Emails from Facebook, Suspicious emails, Email preferences, Password reset emails, Confirmation and reactivation emails, Email notifications, Reporting abuse on Facebook, Someone is attacking or harassing me, Reporting abuse, Abusive site content and Sensitive issues.
If none of these answered your problem you can file a report at http://www.facebook.com/help/?page=1023. Check your emails for any replies from Facebook. You might also think back if you installed any application recently that might cause any trojans or viruses that harmed you PC. Please comment below if this article helped you restore your Facebook account.