We've got a motu 828 gathering dust in my office. Don't ask why...I don't know. We only need to get 2 tracks in at a time, and our current setup works fine (lucid adc spdif into an m-audio delta dio card). However, I tried to setup the motu just so we can get a backup system that works (and to see if the quality is any better). I downloaded the current drivers, but the computer wouldn't recognize any firewire input. I don't think it's the firewire card though cause it'll recognize a firewire hard drive just fine. We're running XP SP2 because the organization requires it for all pcs. I read on the motu site that there are often issues with firewire devices on sp2. Is there any way to solve this besides petitioning the organization to let us remove sp2? I don't really want to make any major changes because our current system is working fine for our purposes, but it frustrates me that I can't get the motu functioning in our setup.
computer has a raided terabyte hard drive, 2gb ram, dual 3ghz processors.

When you installed the driver package from MOTU, did it install the Firewire Audio Control Panel? Should be an icon on your desktop if it did.

If so, open it and see if it recognizes that there's an 828 connected.

My 828 is currently connected to a WIN XP SP2 machine and working, and I don't recall doing anything different to configure it for that machine.

Sometimes there are issues with the chipset used on 3rd party firewire cards; if I remember, the MOTUs like the Oxford chipset.

And the cables need to be six pin on both sides- one of those 6 to 4 cables won't work with the MOTU.

Yes. Like clocker bob mentioned, you should check and see what the chipset of the firewire card is. The MOTU recommends the T.I. (Texas Instruments) based firewire cards for their firewire stuff. They do not recommend any others and have many claims to issues from non-T.I. based cards.
I also have a system based around Win XP SP2 and haven't had a single problem after setting up. I am using some cheap Belkin firewire card ($20 at Best Buy) and made sure it had the T.I. before purchasing. No problems to speak of.
Sounds like that could very well be your problem.

all the best

-Darrill