Hi,   Previously, you mentioned about RAID options, did you remember you had RAID settings? If yes, you can change the SATA settings to RAID mode and try boot. 
After a windows update (windows 2012 R2), i restarted the server and i couldn't connect with remote desktop. The server also couldn't see my monitor. I removed the CMOS battery and i finally got a view of the bios. But i also got the following message: "PXE:E53: No boot filename received. PXE-M0F: Exiting Broadcom PXE ROM. No boot device available. Current boot mode is set to BIOS."   I can see the hard disks in the BIOS. If i set the boot mode to UEFI, i can't see the hard disks! I also can't see any RAID options!
Dell T110 II no boot device