Send to A: gone…

On three WinXP pro klients and two Win2k pro klients in my LAN there is a problem. usually, if you right-click a file on the desktop you get several “send to” choises. Among them are “send to: e-mail recipient, desktop, my documents and floppy (A:),among others. On theses clients the choise of sending to A: has disappeared. I don’t know how, why nor when this happened, but some users are complaining awfully. How can I get the “send to: A:” back on the menu that appears when I right click a file?