Some PCs just won't work well with XboxHDM at least for me in my case I tried on my main compaq but it wouldn't do jack at the locking stage nor detect the xbox hdd, but did better when I switched over to a Dell inspiron desktop, worked like a charm but it sucks cuz I now have to keep this PoS PC around for whenever I need to prep a harddrive or lock it for the xbox, it serves no other purpose other than that
But if you want I can prep the HDD for you just kick me the eeprom and HDD and I'll kick it back your way, for shipping but if you can find another desktop and try it out go for it man!