Problem:
You can't log In, page just reads "Welcome Guest" after each attempt to log
in, instead of "Logged in as: user name".

Solution:
Just delete your cookies and internet files
From Internet Explorer's Tool Bar, "Tools >> Internet Options >> Delete
Cookies..."

and:

"Tools >> Internet Options >> Delete Files..." (also check "Delete All
Offline Content"):

Close all open IE and restart.

Now you should be good to go.

Thanks to KD6AAJ.