do not scan the media for defects. you do not need to mess with the HDD.
from what you have said the HDD is ok and your SCSI set-up is also ok.
boot the PC, load some software and image the HDD to a file.
power off, replace HDD with an identical one, re-boot PC, re-load same
software and write backed-up HDD file image to new HDD.
the DMI error is a different problem. You can try to reset the DMI Pool Data in the BIOS
by defaulting the settings. Or better Google for the error and you will find the answer.
something like this.....
Computer stops at verifying DMI pool data....
also, ensure in the SCSI controller settings that the boot device is not SCSI ID#1
If it is, just set the boot device to something else, not ID 1
You should be booting from your regular Windows HDD.