To start with I buildt a 900 Thunderbird on Asus board,ata 100 and ata66,the hard drive on the 100 and the Hitachi DvD/master and Acer cd rw/slave on the primary 66,All was harmony then one day I would get a fault any time I tried to use the Dvd,The cdrw works fine,the device manager says all is good,the drivers are good,I even reloaded windows 98 se ,heres the fault code, exception OE 0028:5B9B0C1 in VxD called from 0028:C1839898 in VxD scsilhlp(03)+00000508 then it goes on about pushing any key,is there any cheat sheats on these fault codes,Im taking an A+ course but havent gotten to this part yet,or is it something you pick up on your own,oh yea the bios are good too,every thing else works great but what I told you allready Thanks