First thing... make sure you're using the same address everytime. Stick with tartan37.com. Some folks are still using the t37.down2thec.com that we started out with. If they cause and email to be sent, (topic watch or PM) it uses that address. Whatever you choose, be consistent since when you go to an address it uses that address to place a cookie in your cache. (mmmm... cookies...)
Second, try your internet options and clear your cookies. This will effect other sites though so if you don't want to log into your other places you can hit "Show Files" and search for anything from Tartan37.com or t37.down2thec.com and delete that. Next time you log in it should be fine.