I hate to state the obvious but if you get the message incorrect password it means neither of the passwords you entered will have matched the one originally entered on registering and it can hardly be a surprise to get the message you are already registered if you enter the same email address or user name when attempting to register a second time.
The most common advice for the wrong password problem is to check that you haven't got caps lock turned on. Can't think of anything better.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.