Memery loss

Hi- I don't know if anyone has this problem. I have installed FSX on my Emachines and go on the multiplayer often. A few days ago when I turned on my comp. there were things missing on my desktop. Even the backround was changed to the default. There are like holes missing in my files. I have to restore my computer to an earlier date. I am not sure if this is a problem with the multiplayer but, it is screwing up my computer. I do have both of my firewalls on whenever I play FSX. If anyone could help, it would be greatly appreciated. 😞