Three folders from desktop disappeared from my desktop,without me deleting them.?

Hey everybody please HELP ME!!! I will tell you all that I think it haves a connectionto what happend. I have Windows XP. Now,I don't know if what I am going to tell you now has a connection with what happend,but I will tell you anyway. One day,I opened the search box and just for curiosity I wanted to try something.I selected that I want to find "Pictures" and I typed "A" or I didn't type anything,I don't remember.But I was amazed.All the old pictures that I don't have anymore appeared there!All my old pictures that I thought I lost. Ok,I was happy.But then,when I restarted my computer,three folders disappeared from my desktop.I was so sad,because I know I didn't delete them.There I kept a lot of pictures,really A LOT. Yesterday it happend again.Four folders from one folder disappeared.I deleted some pictures,but I didn't delete the folders.I looked in the Trash Bin and the pictures I deleted were there,but the folders weren't..I didn't deleted them..I don't care so much about the folders from yesterday but I care a lot about the three folders full of pictures..PLEASE SOMEBODY HELP ME !!!