(Mail and posting) 

Could it be an issue with the jumper settings on the replacement drives?  Probably "cable detect" is the best setting to try, if it has that, but you might experiment with all three choices (cable detect, master, slave).  Also try switching the mb end of the ribbon cable to the other IDE (ATA) connector on the mb, or putting the HDD on the secondary cable behind the CDROM.  (neither of those will make the computer fully functional, but I'm suggesting them as a way of figuring out what's going on.)

If/when those Acers start seeing the harddrives, we have some Ghost images for the 5200 from another school, or driver CDs if you load a non-Acer-specific Windows installer and they then have trouble with video depth or network adapter -- like Compaq, Acer had the habit of using components that Windows 2000 didn't list.  

 Thanks for your reports and all your work,

  ==Mitch