Windows 7: Dual Boot Installation issue

Trying to add dual boot and xp pro x64 following instructions in posting "Dual Boot Installation with Windows 7 and XP by Brinks 04-28-09"
Refer to: METHOD TWO Windows 7 installed first.

In step 2. it says to insert XP installer disc and reboot. Wait for prompt to press any key to boot.

My question is: why does my computer open windows 7 instead of prompting me to boot the XP installation by pressing any key. I rearranged my BIOS to USB/CDROM to boot first.

My second question is: must I defer from the instrucrions above and delete windows from my computer and later try to add windows 7 after XP is running? If so, how do I delete Windows?

You didn't say what the make and model of your computer was so I can't check the manual, but many newr computers allow you to press F12 during boot to get the Boot Selection Menu, and from there you can choose CD/DVD as the boot source.

Did you burn the CD yourself? have you used it before to boot?

Do you have the latest BIOS version from your computer's Support Downloads page for your model?

Check first bootup screen or Enter Setup to see current version

dup

acer laptop as5517-1208 i month old with win 7 home prem
installation disc is xp pro w/sp2c 64-bit oem authenticity certified by microsoft

2nd partition set up (logical)

wondering if win 7 setup prevents installing older windows xp
and if partion with win 7 and boot must be formatted before xp installation will be recognized.

Why did you format second patition logical? OS's should go on Primary partitions.

Reformat the partition primary and boot from the installer to install there.

It may need the SATA controller put into the installer.

the 3 primary partitions were taken; CDROM drive,SYSTEM RESERVED and Windows 7

CD ROM is not a primary partition, You can format it primary to install XP.