I have tried one drive at a time.. both the same.. I can see some jumpers on the back right hand side.. one is set to 1 the other 2.. I see a access light for about 3/4 sec and get 4 chuck of the drive then it stops..
What I would try is, dont connect both 5.25 drives as I think one is set as Drive 1 and the other as drive 2. Try one at a time and see if it boots with just one installed, if it doesnt work remove that one and try the other one. Find out wether the 3.5 drive you just bought is set up as drive 1 or 2.
I think you ment to post this in the EII forum not in the EIII.
rtech