Clone Disk - Random Reboot

I have dozend of idendical PCs - same mainboard, vga, HDD, LAN, RAM .. all is the same

instead of installing each PC manuell I setup one PC and use Acronis or Ghost to DNA copy the hard disk sector by sector

for xp64 all is working like a charm - after clone I set IP and PC name and that it

for Windows 7 prof. I do the same but my PC randomly reboot within 3min to 40min

I have

-no hint in event log (expect impropper shutdown)

-stoped most services

-killed all task

-no bluescreen, popup, error message

-"disable reboot on system failur" do not affect

-disabled all onboard hardware bios and disabled non importent devices

-lastest drivers (or factory drivers)

-disable all "energy save" options

-installed all Windows 7 updates and fixes

-Windows 7 boot without problems

-common up to date hardware

only "save mode" is stabil and not reboot (within 12 hour tested)

I install Windows 7 -> plug disk to other PC (new hardware found message about HDD) -> pc permanent reboot randomly within 3 min -> disk back to source PC -> all fine

I have no clue what to do.