The HD you require is an old standard IDE drive, it's actually called a 40pin
parallel ATA connector, or
PATA, as opposed to
serial ATA (SATA)
The numbers, if any, are on the motherboard itself, I'm not concerned with what fan you have, tho' I am pretty sure you have an oldish system.
Take the HD out, pop along to PCWorld and ask for the same 'type', not necessary the same make and I'm sure they'll have what you need.
You are sure your HD is nucking fackard, yes?
http://www.maxtone.com/intel-mb.html