Solution is pretty simple: Boot from windows CD or USB drive.
When you see windows setup screen press "Shift" + "F10", this open command prompt.
Then you need to replace utilman.exe file to cmd.exe to do this enter following commands:
copy d:\windows\system32\utilman.exe d:\
copy /y d:\windows\system32\cmd.exe d:\windows\system32\utilman.exe
Usually windows is located on drive d: if it is located in different drive correct commands accordingly.
Now type:
wpeutil reboot
after PC reboots and you see login screen press "Easy Of Access" icon and command prompt opens.
Now you can enable disabled users. For example if you want to enable disabled builtin administrator:
net user Administrator /active:yes
Now reboot computer and try to login with administrator account.