Hi glenjames52,
As there is no output to the headphones, the headphone socket ''may'' be faulty or loose from the systemboard, . This may also be the reason why the speakers do not work. There is a contact inside the socket which is used to advise the audio controller that there is a headphone jack inserted and to disconnect the sound from the speakers and connect it to the headphones and to connect the sound back to the speakers and to disconnect the headphones when it is removed.
If it is faulty or just loose, either way you will have to remove the systemboard to gain access to the headphone socket so as to either replace it or re-solder it back onto the systemboard.
Here is a link to the service manual for your Dell Vostro 1015. It describes the procedure how to remove the systemboard. On p.40 it shows the headphone socket mounted on the systemboard.
http://downloads.dell.com/manuals/all-products/esuprt_laptop/esuprt_vostro_notebook/vostro-1015_service%20manual_en-us.pdf