Getting rid of “Archives” on default theme sidebar

Hello all. I’m a new user working with default theme 1.6. I reset Permalinks using index.php/ (“almost pretty”), and made “topics” the category base, which got me the results I wanted on all the sidebar links EXCEPT the default month link (September) under “Archives” – it has ceased working.

I have created a separate Archive Index page on the mainpage and would prefer to just get rid of the default Archive header and month-link provided, but would settle for making the month-link work again.

Any ideas on how to achieve either of these ends would be greatly appreciated!