Unattended login onto a forum account

I am a member of a professional's forum and everything would be great if it wasnt for one glitch. The forum requires its members to login once every 10 days, otherwise their accounts are deleted.
As I often tend to stay away from the internet for over 10 days, my account gets deleted notoriously which is very annoying.
I tried to contact the administrator but seems it's a no-go option.

Therefore, I want to ask whether there is some program (that executes itself [logs in] when windows starts up, then terminates), shell script, web bowser plugin (Opera preferably) or any other way that would use my sure name and password to logon on the forum once every 8-9 days unattended?

I would be very grateful for any suggestions.