So I use a hard drive tray which usually works fine but every couple of months I'll get no boot, no Bios, just a black screen and various led's. You can see a previous post at https://www.techspot.com/community/topics/stumper-no-bios-or-video.183780/ but Saturday I had my mouse freeze and couldn't get any control. Re-boot attempt gave a DMI pool data error. Surfing yields a dozen possible reasons for that error. Ended up re-setting the Bios solved. I use 7 (64b), XP and rarely Linux Mint, all on different drives. The guy who helped me says Bios 'interacts' with data in the MBR on the different drives. I have never read anything stating Bios can get mixed up due to which hard drive or OS, as Bios passes control off to MBR and then OS, regardless of which sata cable being used. I agree the drive tray must be confusing the Bios but don't understand how. Recently I haven't even had Mint installed so I don't think the grub is a culprit. Anyone know how using a tray and different drives could change settings in Bios? Goes against what I learned.