I have the same problem with a Dell D620. It is a SigmaTel High Definition Audio CODEC even though HWIDS doesn't list it as that. Here are the HWIDS after the right driver has been installed.
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PCI Devices
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PCI\VEN_10DE&DEV_01D7&SUBSYS_01C21028&REV_A1\4&1C9EC085&0&0008: NVIDIA Quadro NVS 110M
PCI\VEN_1217&DEV_6972&SUBSYS_01C21028&REV_40\4&2FE911E8&0&08F0: O2Micro OZ6912 CardBus Controller
PCI\VEN_14E4&DEV_1600&SUBSYS_01C21028&REV_02\4&378EDFA4&0&00E2: Broadcom NetXtreme 57xx Gigabit Controller
PCI\VEN_14E4&DEV_4311&SUBSYS_00071028&REV_01\4&360A6DE&0&00E1: Dell Wireless 1390 WLAN Mini-Card
PCI\VEN_8086&DEV_2448&SUBSYS_00000000&REV_E1\3&61AAA01&0&F0 : Intel(R) 82801 PCI Bridge - 2448
PCI\VEN_8086&DEV_27A0&SUBSYS_00000000&REV_03\3&61AAA01&0&00 : Mobile Intel(R) 945GM/GU/PM/GMS/940GML/943GML and Intel(R) 945GT Express Processor to DRAM Controller - 27A0
PCI\VEN_8086&DEV_27A1&SUBSYS_00000000&REV_03\3&61AAA01&0&08 : Mobile Intel(R) 945GM/GU/PM/GMS/940GML/943GML and Intel(R) 945GT Express PCI Express Root Port - 27A1
PCI\VEN_8086&DEV_27B9&SUBSYS_00000000&REV_01\3&61AAA01&0&F8 : Intel(R) 82801GBM (ICH7-M/U) LPC Interface Controller - 27B9
PCI\VEN_8086&DEV_27C4&SUBSYS_01C21028&REV_01\3&61AAA01&0&FA : Intel(R) 82801GBM/GHM (ICH7-M Family) Serial ATA Storage Controller - 27C4
PCI\VEN_8086&DEV_27C8&SUBSYS_01C21028&REV_01\3&61AAA01&0&E8 : Intel(R) 82801G (ICH7 Family) USB Universal Host Controller - 27C8
PCI\VEN_8086&DEV_27C9&SUBSYS_01C21028&REV_01\3&61AAA01&0&E9 : Intel(R) 82801G (ICH7 Family) USB Universal Host Controller - 27C9
PCI\VEN_8086&DEV_27CA&SUBSYS_01C21028&REV_01\3&61AAA01&0&EA : Intel(R) 82801G (ICH7 Family) USB Universal Host Controller - 27CA
PCI\VEN_8086&DEV_27CB&SUBSYS_01C21028&REV_01\3&61AAA01&0&EB : Intel(R) 82801G (ICH7 Family) USB Universal Host Controller - 27CB
PCI\VEN_8086&DEV_27CC&SUBSYS_01C21028&REV_01\3&61AAA01&0&EF : Intel(R) 82801G (ICH7 Family) USB2 Enhanced Host Controller - 27CC
PCI\VEN_8086&DEV_27D0&SUBSYS_00000000&REV_01\3&61AAA01&0&E0 : Intel(R) 82801G (ICH7 Family) PCI Express Root Port - 27D0
PCI\VEN_8086&DEV_27D2&SUBSYS_00000000&REV_01\3&61AAA01&0&E1 : Intel(R) 82801G (ICH7 Family) PCI Express Root Port - 27D2
PCI\VEN_8086&DEV_27D4&SUBSYS_00000000&REV_01\3&61AAA01&0&E2 : Intel(R) 82801G (ICH7 Family) PCI Express Root Port - 27D4
PCI\VEN_8086&DEV_27D8&SUBSYS_01C21028&REV_01\3&61AAA01&0&D8 : Microsoft UAA Bus Driver for High Definition Audio
PCI\VEN_8086&DEV_27DA&SUBSYS_01C21028&REV_01\3&61AAA01&0&FB : Intel(R) 82801G (ICH7 Family) SMBus Controller - 27DA
19 matching device(s) found.
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USB Devices
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USB\ROOT_HUB\4&16B3F35C&0 : USB Root Hub
USB\ROOT_HUB\4&3357D24F&0 : USB Root Hub
USB\ROOT_HUB\4&529CAA5&0 : USB Root Hub
USB\ROOT_HUB\4&84DA6E5&0 : USB Root Hub
USB\ROOT_HUB20\4&167C9B3&0 : USB Root Hub
USB\VID_0B97&PID_7761\6&75861D2&0&3 : Generic USB Hub
USB\VID_0B97&PID_7762\7&312B4FD&0&2 : USB Smart Card reader
USB\VID_413C&PID_A005\5&1187D97F&0&2 : Generic USB Hub
8 matching device(s) found.
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Input Devices
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No matching devices found.
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ACPI Devices
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ACPI\ACPI0003\2&DABA3FF&0 : Microsoft AC Adapter
ACPI\GENUINEINTEL_-_X86_FAMILY_6_MODEL_14\_0 : Genuine Intel(R) CPU T2500 @ 2.00GHz
ACPI\GENUINEINTEL_-_X86_FAMILY_6_MODEL_14\_1 : Genuine Intel(R) CPU T2500 @ 2.00GHz
ACPI\PNP0000\4&25E2FF18&0 : Programmable interrupt controller
ACPI\PNP0100\4&25E2FF18&0 : System timer
ACPI\PNP0200\4&25E2FF18&0 : Direct memory access controller
ACPI\PNP0303\4&25E2FF18&0 : Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
ACPI\PNP0501\4&25E2FF18&0 : Communications Port (COM1)
ACPI\PNP0800\4&25E2FF18&0 : System speaker
ACPI\PNP0A03\2&DABA3FF&0 : PCI bus
ACPI\PNP0B00\4&25E2FF18&0 : System CMOS/real time clock
ACPI\PNP0C01\1 : System board
ACPI\PNP0C01\2 : System board
ACPI\PNP0C01\3 : System board
ACPI\PNP0C01\4 : System board
ACPI\PNP0C01\5 : System board
ACPI\PNP0C04\4&25E2FF18&0 : Numeric data processor
ACPI\PNP0C0A\1 : Microsoft ACPI-Compliant Control Method Battery
ACPI\PNP0C0A\2 : Microsoft ACPI-Compliant Control Method Battery
ACPI\PNP0C0C\2&DABA3FF&0 : ACPI Power Button
ACPI\PNP0C0D\2&DABA3FF&0 : ACPI Lid
ACPI\PNP0C0E\2&DABA3FF&0 : ACPI Sleep Button
ACPI\PNP0F13\4&25E2FF18&0 : PS/2 Compatible Mouse
ACPI\THERMALZONE\THM_ : ACPI Thermal Zone
ACPI_HAL\PNP0C08\0 : Microsoft ACPI-Compliant System
ROOT\ACPI_HAL\0000 : ACPI Multiprocessor PC
26 matching device(s) found.