that Sony is a desktop model you should be able to open the case and look at it, like Judas said.
but you may lost the Windows and the use of the recovery CDs/DVD if you change the board yourself.
you can visit this page and fill in your question...
Accessory / Parts Research Request
http://servicesales.sel.sony.com/web/partsResearch.do
or if you live in the US. you can call 1-800-488-SONY(7669) for the Sony CS representatives.
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Q9300 @ 500FSB
Q9300 @ 3.60GHz
4x1GB DDR2-1333 (PC2-10666)
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Don't worry overly much about whether a specific KB article exists for your version of Windows.
Standard practice is to grab whatever's available and apply the principles.
(I grabbed from the web. Written by someone, somewhere on the web)