No cd /dvd to install windows

[josbd]

I have an Alienware x51 r1. In short, the cd drive died some time ago, and I have been using an external drive. The hdd went down recently, so I have replaced that and need to reinstall win 7. I have set the pc to boot from the external drive with win 7 disk in setup utility, but on boot up all I get is the Alienware screen, then "no boot device a available, press any key to reboot the system.

If anyone can help with this, I would be very grateful!

 

[hang-the-9]

Your title and post do not match, you said "No DVD to install Windows" but in the post you said you are booting from an external drive with the disk, so do you have a Windows disk or not? You can't select the boot drive when the system is booting? There should be a Function key selection to manually select the boot drive, select the external with your Windows disk in it (if you have the disk). If your external drive a CD only reader or DVD also? Windows 7 is a DVD setup.