Something that has been driving me crazy is the search in Outlook 7. You can't search on a folder by right clicking and searching that way you used to.
What you need to do to fix this is open up Outlook 2007. Right next to the search box their is a down arrow which will allow you to change the search functionality of the search box. See image:
After you click on the down arrow, click on the search options which will take you to the following screen:
Inside this windows you will see where I put an arrow to change the option to search through all folders for email or search just the currently selected folder that you are in.
So, from now on if you want to search just one folder you can click on the folder that you want to search in and just search the contents of that folder.