Can only see 15 posts in wp-admin; previous entries link not working

When I am logged into the wp-admin panel and then click on “Manage” I am shown only the 15 most recent posts. If I click on the link at the bottom of the list labeled “Previous Entries” I am taken to the Dashboard rather than to the 15 previous post links. This also happens if I filter by month, with only the 15 most recent showing up and then any attempt to follow the “Previous Entries”link taking me back to Dashboard. This was not happening until I upgraded from 2.0 (I think) to 2.3. I need to go back to all my posts to do some reformatting and the only way I can access the earlier posts is to flip back and forth between the blog itself and the admin panel, entering key words from each individual title and filtering by month. This is excruciating! Is there something I can do to fix this problem? I don’t know much about php but can probably modify a file if I get specific instructions. Will really appreciate any help. Site is holeinthedonut.com