I don't know who told you that partitioning a drive isn't good, but they're mistaken.
In order to use a HD, it MUST have at least one partition on it.
Anyway, what I would recommend doing is disconnecting your old HD, connect the new drive as master (refer to manual that came with it), use a Win 98 boot disk and format the new drive, then reconnect the old drive, set the new drive to slave and make sure the old drive is set to master.
You could also install it without ever connecting your old HD, but many people have lost all their personal files by doing that.
I recommend just following the steps above.