Hardware Secrets posted a tutorial about How to Enable Processor-Based Security
At last PCs operating under Windows have a security level similar to that used by high performance servers. This technology – known under names that vary from manufacturer to manufacturer, such as NX (No eXecute), EVP (Enhanced Virus Protection), XD (eXecute Disable), or DEP (Data Execution Protection) – allows the processor itself to detect when a malicious code (such as a virus or a Trojan horse) is attempting to run and automatically disables such code, "drowning" the virus. In this short tutorial we will teach you how to enable this feature.How to Enable Processor-Based Security