I said: So you must have inadvertently deleted your own account from the ACE. The "big string of numbers seperated by dashes" are the SIDs of the users. In general for a shared folder (not a system folder) you only need the Administrator or an admin user or the Creator Owner to have Full Control. In my shared folder > Sharing tab, I only have Authenticated Users (which means not Everyone (without password), nor the Guest can access it). Have a look: http://support.microsoft.com/default.aspx?...kb;en-us;810881 Folder sharing and security are part of MCP exam and if you can, have a look in the exam books and books on Win XP. I find the systematic approach a lot better than the bits of info you get on the internet. There're quite a few things to learn.