My understanding is usually anything not overwritten can be salvaged if the drive isn't damaged. A system restore may have re-written on top of the old data which may mean it's gone forever.
My neighbor had me over to his house to clear his digital camera of photos because it was full and all new to him. Week earlier I had shown him how to download to his computer. I asked him twice if he wanted all his vacation photos removed and he said yes. After I deleted everything from the camera, he asked if they went onto the computer!?! I told him they are just "Gone!" And felt that sinking feeling in the pit of the old stomach... The moron hadn't transferred the photos to his computer yet.
I found a freeware program that I installed on his machine. Completely free (not the bait and switch) and it worked like a charm resurrecting the 240 jpgs that had been erased.
