http://support.dell.com/support/downloads/driverslist.aspx?os=WLH&catid=-1&dateid=-1&impid=-1&osl=EN&typeid=-1&formatid=-1&servicetag=&SystemID=INSPIRONI6400%2FE1505&hidos=WW1&hidlang=en&TabIndex=&scanSupported=False&scanConsent=False
LOOK under network tab,and try the vista drivers,or you can try to install it from within the device manager!
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