Can't login to admin

I have just go this installed on localhost (IIS6, SQL Server EXpress) but when I try to login with the credentials I supplied in the setup nothing happens. The form refreshes and I'm still looking at the login page. I have checked in the customer table that those credentials are admin and active which they are. Created a new user and made them admin too but it still doesn't work. Also I notice if I login to the store it's not registering; trying to proceed to the checkout just dumps me back at the registration form. Is it a cookie not being written? I don't know. Stumped.

Never mind. I deleted everything out of the root and unzipped it back in from the rar. Deleted the database and re-created it and it all seems to be working now