Vanishing Files...?

Yesterday I was trying to arrange my pictures into folders so I could burn them on to disks. I had all my folders in order, went to burn them, and they were no longer there. A friend helped me out and told me to do a .JPG search and it would pull up every picture I had in my computer. This did NOT work in recovering the original photos, but I did how ever find the smaller ones I cropped and saved in my documents. So I copied all of them, arrange them into a folder and low and behold they disappeared too! So I did another .JPG search again and couldn't find any of the pictures I had just recovered. I have searched everywhere I know to look, I have done a system restore with no luck, they are just no where to be found! This morning I woke up and noticed that limewire and yahoo messenger I just installed last week are no longer in my computer either. I went to add and remove programs to see if maybe just the icons disappeared and its like I never installed them. I just don't understand how something can be there, and the next day they are gone! Every single picture of my daughter is missing and I am heartbroken. Any suggestion on what to do next? Could it be possible that I have a virus? I have McAfee virus protection and its not catching anything unusual. I am just at a loss for words. Please help me, pretty please with sugar on top!!! ~Jess

Vanishing Files...?internet security