Can u tell the process how u r trying to boot from CD
and where this process gets abort.

If you are being dropped down during the boot from a linux cd to the
Bash shell (which in rare cases happens) then something odd is happening.

But a little more info is needed. What kind of distro are you
booting? Does the shell show up? Is there an install starting and are
you being dropped to the shell? Or are the disks simply not read?

I tell you what ... I bloody give up - I really do ...

I've spent the last month, almost on a daily basis trying to get this thing
to boot a Linux CD/DVD, all to no avail - the boot sequence would get as far
as ...

Verifying DMA Pool ...
Booting from CD/DVD

... and then just hang - nothing (I've even left it for a couple of hours
morse than once, just to see if it woke up - nope).

Not appearing to be happy with the bootstrap, methinks (hence my reluctance
to go any further with it).

Tried multiple distros, burned onto multiple disks (just in case the disk
was the problem) - Ubuntu, Kubunti, Xubuntu, gOS, PCLinuxOS, Mepis, that
nasty little Open-SuSE KDE4 disk, and others (all of which have happily
booted on my old machine), all with the same results ...

However, this morning I try again, just to be accurate as to where it's
failing, and the b*st*rd thing boots, as if nothing was ever wrong ...

It's as though it was just waiting for me to ask for help, so that it could
make me look like a complete idiot (they do things like that, trust me, I
know ...)

Funny enough most ICT/IT personell hate pc's too...

You could check the HCL (Hardware compatibility list) if your
mainboard and controllers are supported or simply goto Gigabyte and
check if they have update firmware.

I had a right weird problem with an ASUS P4P 800 once. It could
install and then came up with a either a grub error or a Kernel panic.
Turned out to be a bios problem, updated it and never had that problem
again.

But, glad to hear that it now boots, you could try for a dual boot
now or if you don't trust it, how about a USB disk.

Yeah - my background's UNIX support ... Solaris/HP-UX ... on proper
workstations ...

The more I have to do with computers, the more convinced I become that
we have accidentally created artificial intelligence - nothing can be so
creatively malicious as computers are without some kind of conscious
direction. And, unlike man, there's no argument over where they came
from - they *know* who created them; they *know* who to blame! :-)

Are you sure about this? The reason I question it is that when my
motherboard went bonkers (a couple of caps blew), and it would
intermittently boot. When it did successfully boot, it was only after
it entered a loop with Verifying DMI Pool Data...

The DMI is a BIOS level database of all of the hardware on your machine.

I would check your messages again to see if it was DMI rather than DMA
which doesn't make any sense (at least to me).

Another thing to check is that since you put together this machine
does it pass the System Requirements for Linux.

I assume you have entered the BIOS and checked to see that the boot
order is set to boot first from CD followed by hard drive, leaving out
the floppy.

Also, is there another motherboard you can check the system with?

Your description somewhat sounds like there might be a hardware
problem (check the caps on the motherboard). Can't be sure though.

It might very well have been DMI, on reflection (had to disassemble the kit
due to visitors - will get another chance at it all sometime on Sunday),
however this is not something I'm concerned about as (a) it's a startup
message I see on an awful lot of machines - seems pretty much par for the
course, and (b) I wasn't seeing any problems booting XP-based disks, just
Linux ones, although these appear to be quite happy now - thought it might
have been a firmware issue (even bought a new DVD drive, just in case that
was the problem (I'd tried a couple of old CD drives, with the same
result)), or a combination of the actual hardware/firmware revisions, but
everything suddenly started working ok (albeit with the new DVD drive, but
not immediately after I'd installed it) - I guess something simply needed
settling in - I know from bitter experience just how awkward these things
can be when they feel like it .... I've built/rebuilt enough of the things
over the years to find that out ...

I've just built a new machine around a Gigabyte G33M DS2R motherboard, but
find that I'm unable to boot from Linux CDs. Windows-based CDs appear, so
far, to boot fine, but Linux ones don't seem to want to know. I've tried
several different CD/DVD drives, all to no avail. Although I know that I can
boot from a floppy, in order to get at the CD, I'm concerned that if I do go
this route, the motherboard may not be able to boot from the HDD for the
same reasons (whatever thay may be). Is this common with these motherboards?
Is there a quick and easy fix?Can anybody shed any light into this for me?

If you go to your bios and pick the boot order. Pick the CD rom drive at the
first and then your HD second.
In fact you can leave it that way. The machine when you turn it on will
check the CD rom and then the HD to load.
Your Instruction book that came with the MB should tell you more.