[AsRock]

Umm had no problems with the demo. Maybe you need to turn off DEP and turn on compatibility mode ?

How to turn off DEP

Right click My Computer select Properties
Left Click Advanced Tab
Under Performance Click settings
Tabs at top Ones is called Data Execution Prevention Click it.
Select second option Turn on DEP for all programs and services except those i select.
Reboot be needed i believe
Add your program to the list

How t turn on Compatibility Mode

Right click the Crysis shortcut and select properties
The tab called Compatibility click it
Under Compatibility Mode tick the box and try putting it on Windows XP.


Other thoughts are you the admin of computer ?. And have you updated XP x64 with SP2 and all other updates ?.