Dell Studio 1558 help =(

Accidentally formatted my laptop Studio with windows 7 and lost the recovery partition and I called to Dell support and they told me I could restore it using a Data Safe Local back up file from another Dell but I go to the Factory image restore options pressing F8, I see the Factory Image Restore but I don't know how to use it, I can open the USB and see all the files but nothing happens. Do I need to select an specific file or something like that? Please. I would appreciate some help. Suggestions also accepted.