As discovered by a colleague some time ago there is a bug in Windows 7 where it takes 30 seconds+ to login when the background is set to a solid color. When having an image as a background the login is instant. The problem does not involve the first logon, but every logon after you have started the machine and logged in for the first time. Now, there is a fix for this interesting problem. Please see for http://support.microsoft.com/default.aspx?scid=kb;en-us;977346 more information and to download the hotfix.