My dads Win XP machine had an extra HDD he wasn't using that was purchased from a store about 1 year ago. So I took it out of his machine and put it into my G5 and it doesn't even see its there. Specs... Dual 1.8 G5 PowerMac 10.4.11 500GB Western Digital SATA II Caviar Blue 16mb WD5000AAKX I know G5 is fine because I just took out the original 80GB HDD and put the newer WD drive in its place. I also have a 320GB HDD in slot B with Tiger on it. I went to WD website and they said it works with Tiger and that the OS should have everything needed to see it. I put the WD drive into slot A while the boot drive is in slot B, would that matter? I know the WD drive is fine as I just used it in my dads dell last week. Thanks in advance.