unable to install ubuntu 11.10 from disc to a hard drive not give any installation type options

unable to install ubuntu 11.10 from disc to a hard drive not give any installation type options .Is a new 11.10 dics from ubuntu not a downloaded copy .the disc allows you to try Ubuntu all works well .when try to do a full install .goes to welcome screen ask to pick country . then to nxt screen as for min 4.4 gb extra ,connceted to internet .then to nxt screen get. get installation type screen shiows a blank partition table .with drop down ...device for boot loader installation../dev/da/ ..and quit ,back.install now all buttons working ...all other buttons not able to use ..when click on install now get message.. no root file system is defined ,please correct this from partition menu ..the menu is blank and no buttons work .only ubuntu to be installed on the drive ,tryed format drive with gpart with in the try ubuntu mode still no good no options given also like install on full disc or longside options. .the hard was use for windows 7 before but beem formated .have check hard drive and shows no faults .if it a simple partition thing what is the best sizes to use and how .drive is seagate 1tb drive .amd f4100 .4gb ram.