About a week ago, my Maxtor 120gb HDD suddenly disappeared in Win XP (as in you can't see the drives in "my computer"). I rebooted and ever since then that HDD has been very slow. I thought it's dying, but Speedfan's reading of its S.M.A.R.T shows perfect health. Then I discovered that it's running in PIO mode. I have never checked before what mode it's running in, but it used to work just fine (as in both running with good speeds, and no hardware interrupts consuming 50% CPU load) with my WD 120GB on the same ATA133 cable, with the WD HDD being the master. I've told the Maxtor to run in various UDMA modes in the bios, but it doesn't help. What to do?