远程桌面只显示桌面背景颜色

Once in a while I will connect to Windows XP Pro via RDP, I will be logged on but the screen will just go to light blue - the color of the desktop background. No windows are shown, no response to mouse or keyboard including ctrl-alt-end. If another user logs in forcing me to log out then the next login is fine. This seems to happen randomly.Once in a while I will connect to Windows XP Pr