Flash895.exe is a DOS executable, a utility used when flashing the BIOS from a floppy. It's used in conjunction with the BIOS file, in your case 965PS3.F8 (the latest BIOS revision for that board). You need to run the @BIOS Live Update Utility in order to flash the BIOS from within Windows. You'll want to select the option "Update BIOS NOT through Internet", and then browse to the extracted BIOS file 965PS3.F8
@BIOS
http://www.gigabyte.com.tw/FileList/NewTech/old_motherboard_newtech/tech_a_bios.htm
I believe that board also supports Q-Flash, a BIOS flash utility embedded in Flash ROM... whereas you can update the BIOS from within the current BIOS menu.