I have a gateway m460es and need DVD and...

please do tell the win version and model of dvd-player ( see its label for details)u are using,
do check in the bios, if dvd-drive is being recognized, do check if all cables are connected and if the drive is jumpered properly.

To do so, press F2 or F1 or Del- button during booting, before windows is loading.
browse through IDE-devices, set detection option to auto, exit BIOS saving changes by pressing F10, reboot.

Now insert a windows cd into drive and wait if it will boot frombut it-do not install windows but press F3 to leave setup and reboot from harddisk!
if it uses the cd, the computer recognizes your dvd.

to check if windows can handle the dvd/drive and further instructions, do come back to fixya!