DUH. http://www.blogger.com. Who is buried in Grant's tomb, anyway?
But, you would be wrong. With new Blogger, you are much better off logging in to https://www2.blogger.com/login.g.
The latter is secure, and it uses the scripts written for New Blogger ("www2.blogger.com"). If you don't login thru the latter, consistently, you could have problems that come and go.
- Problems that you solve, temporarily, by clearing cache and cookies.
- Problems that you solve, partially, by checking security on your computer.
- Problems that you solve (when using Internet Explorer), maybe, by permitting cross-frame scripts from "Blogger.Com" (and specific Trusted web sites).
For best results, bookmark https://www2.blogger.com/login.g - and use it - consistently, after you clear cache and cookies.
Also, see Help! My Blog Is Gone!: Login Problem for login problems of general natures.