In a previous thread, you said you'd forgotten your password and I posted a link for you to the password recovery form. That's an automated process and the password should have been emailed to you straight away. It would go to the email address on your profile though, so if you've changed email addresses...
Another option, of course, is simply to change your password. You can do that through your User CP (click on user cp button on top left toolbar, then choose edit email and password from the menu on the left side of the page).
If it isn't a password problem, and you've successfully deleted all your cookies (important because corrupted cookies are usually the problem) and still having trouble logging into the gallery, then perhaps you need to contact Olly (BW's owner) directly to see if he can find your problem.
Moving this to the computer forum.