jyjjy :
It's possible your motherboard can use core2duos. Tell us the brand/model. If you don't know it use CPU-Z;
http://www.cpuid.com/cpuz.php
Intel Pentium D 820
Windows Vista Home Basic Edition (Build 6000)
CPU Arch : 1 CPU - 1 Cores - 1 Threads
CPU PSN : Intel Pentium D CPU 2.80GHz
CPU EXT : MMX SSE SSE2 SSE3 EM64T
CPUID : F.4.7 / Extended : F.4
CPU Cache : L1 : 12 / 16 KB - L2 : 1024 KB
Core : SmithField (90 nm) / Stepping : B0
Freq : 2793.06 MHz (199.5 * 14)
MB Brand : Dell
MB Model : 0WG864
NB : Intel P965/G965 rev C2
SB : Intel 82801HH (ICH8DH) rev B0
GPU Type : NVIDIA GeForce 9800 GT
GPU Clocks : Core 550 MHz / RAM 900 MHz
DirectX Version : 10.0
RAM : 2048 MB DDR2
RAM Speed : Unknown (Unknown) @ N/A
Slot 1 : 512MB (4300)
Slot 1 Manufacturer : Qimonda
Slot 2 : 1024MB (4300)
Slot 2 Manufacturer : A-Data Technology
Slot 3 : 512MB (4300)
Slot 3 Manufacturer : Qimonda