Below is a response to Acronis tech support who has be patiently assisting me. This problem faked me out because my system's boot order "appeared" normal at first. It was trying to boot the external USB hard drive first instead of my Server's internal hard drive array. Maybe this will help others and save them grief: ----------------> I have everything working now. My "Operating System Not Found" error was NOT caused by the Acronis restore. It was the HP Proliant ML150G3 BIOS Setup. Under Boot Order it had hard drives before removable media as expected. But hard drives also had a sub-order list showing the Maxtor OneTouch III external USB hard drive in a boot order "before" the HP Smart Array E200/128 RAID Controller. I moved the Maxtor down below the RAID Controller and then it booted into Windows! I am able to do a full disk image restore (2 partitions) and afterwards I use the HP Proliant ML150G3 drivers CD to update the system. Right now I am doing another test restore to verify reliability and more practice doesn't hurt either! <----------------- Note - When changing the sub-boot order list for the hard drive category in BIOS Setup, at first it didn't keep the change when I re-checked. I was moving items back and forth and "Save Settings and Exit" didn't keep it. It seems it likes it better to change one item at a time. Do a "Save without Exiting" and re-check. Then "Save and Exit" when you are done.