Problem in RB411 after upgrade

Hi all
I have a RB411, which had v3.10 softwares. I just did upgrade to v3.13
and now winbox doesn’t detect the router board.
i tried reset as mentioned by normis http://forum.mikrotik.com/t/reset-rb-411-os-level-4/20932/1
that didn’t solved my problem either
have i done irreversible damage to my board.
Any helping suggestions is greatly appreciated
Thankyou very much

Serial Cable

Thanks Aug
You mean use Serial Cable and connect using hyper terminal.
Thanks