When you start certain computers that run Windows Millennium Edition (Me) with some types of PC Cards inserted in a CardBus slot, the PC Card may not be successfully enumerated. You may hear the PC Card "removal" sound during Windows startup, instead of the PC Card "insertion" sound that indicates successful enumeration of the card.

If you eject and reinsert the PC Card after the computer has finished starting, the card is successfully enumerated, you hear the PC Card "insertion" sound, and the device functions correctly. Also, if you suspend and resume the computer, the PC Card is successfully enumerated, you hear the PC Card "insertion" sound, and the device functions normally.

This problem may occur on certain computers that use Texas Instruments 1420 CardBus controller chip sets and Intel ICH3 main system chip sets. When the TI 1420 CardBus controller is being initialized and is detecting the presence of a PC Card, a spurious power-management event (PME) signal may be generated and passed through the ICH3 chip set. If this occurs when the CardBus socket-services drivers are not able to process the events properly, the processing of the event may encounter an error. This error can result in the card-insertion event being misinterpreted as a card-removal event, and the inserted PC Card may not be successfully enumerated.

The hardware problem with the Texas Instruments 1420 chip set that causes it to generate a spurious PME signal also occurs with the Texas Instruments 4451 CardBus chip set, and results in the symptoms that are documented in the following Microsoft Knowledge Base article:

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Possible workarounds for this issue include:

• You can work around this problem by disabling power-management capabilities for the Texas Instruments 1420 CardBus chip set. To do this:
  1. Start Registry Editor (Regedit.exe).
  2. Locate and click the following key in the registry:
     HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\PCI
  3. On the Edit menu, point to New, and then click DWORD Value. Then, type the value name as indicated below:
     Value name: AC51104C
     Data type: DWORD
     Value data: 0x20000000
  4. Double-click the new value name, type the value data as indicated above, and then click OK.
  5. Quit Registry Editor.
  This workaround has the effect of disabling all power-management functionality that is associated with the CardBus controller. Features such as Wake-on-Ring (for PC Card modems) and Wake-on-LAN (for PC Card network adapters) for inserted PC Card devices are disabled by this workaround. Also, the CardBus controller itself would always be powered on, even if no PC Card is inserted, resulting in a potential slight increase in power consumption and corresponding reduction in battery life when the computer is using battery power.
• Some Original Equipment Manufacturers (OEMs) with certain hardware configurations have resolved a similar problem by modifying the computer's BIOS to read the PME# status line multiple times when it is signaled, and to pass the PME# signal only if the PME# line remains active for more than a brief period (for example, for more than three milliseconds).
• It may be possible to work around this problem in the motherboard hardware by adding appropriate resistance and/or capacitance to the PME# line to suppress (de-bounce) the spurious signal from the Texas Instruments 1420 CardBus controller.

To determine whether your computer contains the components that may produce this symptom, follow these steps:

1. Click Start, point to Settings, and then click Control Panel.
2. Double-click System, and then click the Device Manager tab.
3. Click the plus sign (+) next to PCMCIA Socket to expand the branch.
4. If there are any entries under PCMCIA Socket that read "Texas Instruments PCI-1420 CardBus Controller," your computer contains the CardBus controller chip set that is susceptible to this problem.

This problem is known to occur on the following portable computers that contain the Texas Instruments 1420 CardBus chip set and Intel ICH3 main chip set:

• IBM ThinkPad model T23

This problem is known to occur with the following PC Card devices:

• IBM Microdrive (model DMDM-10340) with IBM PC Card adapter
• Socket LP-E Compact Flash Ethernet card with IBM PC Card adapter