Advice on upgrading HD in an old dell

Hi there,

I have been offered an old dell optiplex, P3 600MHz slot 1 with a
small HD, 2GB from memory, maybe slightly bigger.

I'm after some advice on fitting a larger HD, to use as a media
server. The service tag is; IYA1T, shipped 7/4/2000, but I just
seem to be going around in circles on the dell site and can't find
any info on HD sizes. I don't have the box here yet, so I can't
give much more info at the moment.

I'm not after anything huge, around the 40GB mark will probably
do. Will I see all of a drive this size or am I looking at a 32GB
(or even lower) limit, bios is original and it's running NT4.

Thanks,

Ian