Cant boot into WIndows 8

I have a dell XPS 8500 and I changed some settings in the bios so that I could try to get my pc to boot from a Windows 8.1 Dell restore CD. I changed some setting, however, I keep on getting this message and I can no longer get into bios (i tried pressing F12 and every other function key at boot time with no luck.

I am getting the following message

"

Reboot and select proper boot device or insert boot media in selected"