Comment Spam Disabled my Admin Menu

A spammer left 4 comments and now when I log into my admin panel I only see the following in my menu bar:

dashboard
write
manage
comments

The blogroll, presentation, plugins, users and options are all gone.

I had to delete the comments from the database as those comments had the edit/delete function disabled.

I looked through the menu.php file in the admin folder and I think my permissions may have been reset.

How do I reset my permissions?

Or do I need to delete WP and reinstall it?

Any idea on how to prevent this from happening again?

Thanks!

Sue