BIOS lock??? Help!

Hi guys, hope you can help im going crazy trying to find the solution to this.

I have a Dell OEM CD for WinXP SP3.
Its not a Dell machine im using but i bought the CD AND the product key legitimately.

I'm trying to use this CD to format my HDD and completely reinstall windows. It is a full install disk not just a recovery disc.

When i put it in my drive while windows is already running the drive(F: displays NOTHING. As if it was a blank disc.

I've tried the disc in my laptop and its a real disc with the full WinXP on it. reads fine on the laptop.
I've tried numerous different CD's in the drive on this system and they all work fantastic. I even watched 'Spinal Tap' the movie on DVD on it.

So regardless of any of this i went ahead and tried to use it anyway.
I went into my BIOS, made the cd drive the primary boot and tried it. It ignored it and went straight onto the HDD boot.

So i tried disabling the HDD altogether and when i reboot it comes up with the error message:

'DISK BOOT FAILURE. PLEASE INSERT SYSTEM DISK AND HIT ENTER'

The PC was originally a MEDION PC. I've done some searching and found out that Medion put a 'BIOS lock' on it so that no software other than their own licensed ones can be recovered or reinstalled.

From the Medion website(direct copy/paste):
"What does BIOS lock mean?
A BIOS lock is a technical mechanism that allows you to perform an installation only under certain conditions. A special code, developed by us, prevents the installation of content of external media (e.g. recovery CD) except additional files (driver, tool, etc.), on a PC system other than that of the OEM's (hardware manufacturer)."

Does anyone know a way to bypass this?
I dont even know what BIOS Flashing is but will that work?
There is no password on the BIOS but would removing and replacing the CMOS battery work? - I tried this it didnt work!

The pc is at least 10 years old and is waaaaaay past warranty. Its also had about 3 owners since the original purchaser.
Keeping that in mind. I'm still not out to break any sort of laws so if me even asking this question is breaking a Policy of these forums i apologise. Please inform me and i'll delete it ASAP.

Thanks to anyone that can help.

Baron