I've tried to virtualize one of my physical servers.
I have no problems doing this via Disk2vhd or Acronis Backup&Restore on many machines till now.
For one of IBM servers I couldn't do this.
After trying many methods of making copy of the C:\ drive, nothing worked.
I've always get the BSOD saying: IRQL_NOT_LESS_OR_EQUAL.
I knew that it was caused by the driver problem, but I thought that it's a rather IDE driver ( server has had SCSI disks) which was not included in my system. After adding registry entries, this didn't help too.
After some more research taken, I find out that the real problem was with OSA IPMI Driver.
After uninstalling it on the physical server, restarting it and making new image by disk2vhd, virtual machine started correctly!