Нашел тут .
Вот что людии пишут:

well im not sure that it will work for u or not, but i could find only this method of disabling power keys by registry modification, take a look at this articel:

"I created the binary value "Scancode Map" in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout" and filled it with 00 00 00 00 00 00 00 00 02 00 00 00 00 00 5E ED 00 00 as recommended by wolluf. It didn't work. I read http://www.microsoft.com/hwdev/tech/input/w2kscan-map.a...
and turned right ctrl to nothing filling the value's data with 00 00 00 00 00 00 00 00 02 00 00 00 00 00 1D E0 00 00 00 00. It worked. Then I tried to turn right ctrl into power down key and nothing happened. I tested then with a virtual machine (key substitution done in host machine) and the virtual machine "understood" the power off command issued by pressing the substituted right ctrl key. So this substitution occurs later than power down key processing."

>>above article is taken from the site http://www.tek-tips.com/gpviewthread.cfm/qid/640536/pid/616/lev2/67/lev3/70<<

Hope it helps :)

mahoune