You can do it under the white search box click on the blue bar where you can sort it out. Click Custom. Then click Filter. Then click More Choices. Then TIC the box ONLY ITEMS WITH and Choose NO Attachments. This will allow you to search for messages with no attachments.

To search for messages you Reply to is a little diff. Go back to same spot, but this time click on Messages, then where it says "Search for the words" Type RE and then choose IN the Subject field only. This will allow you to search for the emails with RE "Reply" in the subject line.

Now you should be able to search for emailed with your reply and no attachments.