Home built pc wont install OS

[Narey]

using a new:
motherboard
psu
cpu
ram

and old:
HD
graphics card
DVD RW

i set up my pc, and im pretty sure ive not gone wrong. upon starting it up if lef to its own devices it will try and load windows from the hardrive which obviously wont work because of all the new hardware, so i throw in the windows cd, reset and wait. what happens next is i get told "press any key to boot from cd" however it wont let me press any key. anything i pressed is ignored and it again trys to load from whatevers left on the hardrive

please help

 

[Rik]

Are you using a usb keyboard? If so, is usb legacy support enabled in your bios?

 

[Narey]

that was EXACTLY the problem, phoned my cousin and he told me. thanks alot wasnt expecting that quick a fix