Don't know if this will work but you can try it...
In the Code References window - click on the Options button. In the popup window at the bottom you'll see a textbox that holds the directory location of your code reference tables. Take a look in that folder at those tables - maybe you can do a RECALL ALL on them to get your results back...

>I accidently checked the overwrite previous results checkbox when performing a Search with the Code References tool and lost all my previous results for a Project. Is there any way to restore these previous Results?