When I was clean installing Windows 7 on my desktop, I shut off the computer right when the install was starting because I didn't give the maximum amount of space to the partition, and I didn't think it would cause any harm. So when I rebooted, I got to a screen with some line and the top left corner of the screen and after a while, it turned to a "Missing Bootmgr, Press Ctrl-Alt-Dlt" screen. I'm not sure what to do, all the guides I saw on the internet said to go into the bios and choose boot from cd drive, but I can't even get into the bios. Note I am using an external usb dvd drive and I can access the bios when I take out the harddrive. Anyone know what to do?