Adding new hard drive

[wwp]

I am running xp mce and trying to add an extra hd for storage.
I have installed it in the box and connected the data and power cables
but it does not show up in explorer.
I have tried Partition Magic and Windows disk management but they run
for an hour or more and do nothing.
Could someone tell me how to proceed from here?
Please help if you can.
Thanks
wwp