You need to offer more information about your system. Is it an OEM (Dell, Gateway, etc.) or a custom/home build? If the former, what make/model, if the latter, what motherboard make/model?
* Socket: 775
* Supports the following processors: o Intel Core 2 Quad (Yorkfield core) Q9xxx
o Intel Core 2 Duo (Wolfsdale core) E8xxx
o Intel Core 2 Quad (Kentsfield core) up to Q6600
o Core 2 Duo E6x00 (Conroe core) up to E6700
o Core 2 Duo E4x00 (Conroe core) up to E4400