During the setup procedure of most Windows versions you may press SHIFT F10 to open a comamnd prompt to open a command line.
During EBS setup this is very usefull for installing graphiccard drivers during setup that might not be known by the Win2008 on DVD driver library. For that opening the devicemanager entering devmgmt.msc to the command line prompt is even more helpfull.
You may also open the controlpanel by entering control to the CMD.exe prompt.
If you are using a SAN, then you can use ISCSIcli.exe to connect to the SAN before installing the storage part.
start. (starts the explorer)
to be continued....
(Mail or feedback me if options you know are missing here)