The default file format used by cameras and mobile phones is jpeg, which has the '.jpg' file suffix.
Select Start > Search, and select 'search all files and folders. Enter your search term as '*.jpg ' (without the quote marks). That will find every jpeg file on your PC, irrespective of whether they're in a folder called 'Nokia', 'My Pictures' or anywhere else.
Of course, if you never actually transferred the pictures from your old laptop to your new one, nothing you can do will make them magically appear.
Chris