Comp only start when SSD is running solo

[Najarana]

I bought a M4 crucial 64gb ssd drive recently and after installing it it shows up fine in the initial startup screen but after that the screen goes black (except for that little blinking cmd marker)
But this only happens if i have other drives connected as well. If i disconnect my regular sata drives I can boot the ssd. And if i remove the ssd i can boot my old drives as usual. I've tried switching boot sequences but it doesn't change anything. Does any of you have a clue of what could be wrong? I am using an old Mainboard wich only supports sata 2.

 

[WyomingKnott]

Well, it's "obvious" that it's a boot priority problem. Except that you have already ruled that out!

With both the SSD and the hard drives attached, can you select the old hard drive and boot from it? In other words, does the conflict trash boot entirely or does it allow the older drives to boot.

Is there any controller-mode switching going on here? Were all the installations done in the default IDE-compatibility mode, or did you switch to AHCI mode for the SSD install, or did you have AHCI on all along when you installed to the HDDs?

I'm thrashing around here; I don't have any solid idea yet.

 

[Najarana]

No I can't boot from any drive if both ssd and sata drives are connected. Can boot from ssd if sata are disconnected and vice versa. And I'm quite new at this but I belive all discs are installed with AHCI.