Hi richboyliang and jwgraves,
I had a very similar issue.
New Netgear N300 (NETGEAR WNR2200 N300), purchased 31-Dec-2011.
Started to set up.
Set up LAN and Internet, did not set up Wireless.
Then, using the router's web interface, on a CAT5 cable,
'semi automatically did a firmware upgrade'.
At first, all seemed OK but I noticed that I could login without a password!
After a lot of hunting about on forums at netgear.com
I decided to do a RESET to factory default configuration settings
(by using a paper clip to push the button).
I have documented this atNo login window after firmware upgradehttp://forum1.netgear.com/showthread.php?p=386287#post386287
I now think that quite a few folk have this issue, on several
models of Netgear routers:
I paraphrase - 'following an apparently successful firmware upgrade' one
is now able to 'login without a password'!
So, if I were going to do another firmware upgrade I would do:
1. Backup the settings.
4. Restore the settings from the backup file.RESET to factory default configuration settings
did work for me.