One of the most annoying things about Dell servers is the log-in background. To get rid of it create a text document with the following and rename it to clearwp.reg.
Windows Registry Editor Version 5.00 [HKEY_USERS.DEFAULTControl PanelDesktop] "Wallpaper"="(None)"
You can now run this on individual machines or deploy it via Group Policy. Alternatively, you can manually change this setting using regedit.