The best and most accurate way to download your Dell drivers is via the dell serial number function:
http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=19&l=en&s=dhs&ServiceTag=D7LPP1S&SystemID=PLX_PNT_P4_745&os=WW1&osl=en&catid=&impid=