See a yellow exclamation point next to a device in Device Manager? Don't worry, it's not that uncommon. There are many reasons that a yellow exclamation point might show up in Device Manager - some more serious than others.
The yellow mark itself doesn't give you any valuable information but what it does do is confirm that a Device Manager error code has been generated. To fix whatever problem is going on, you'll need to view this code and troubleshoot accordingly.
Once you know the specific code, you can reference my List of Device Manager Error Codes for a solution.
Note: I often get asked about the "yellow question mark" in Device Manager. The yellow question mark appears as the full sized device icon and will appear when a device is detected but not installed. You can solve this problem by updating the drivers for the device.
There is also a green question mark that can appear in some situations but only in Windows Millennium Edition (ME).
Also, in case you're really paying attention in Device Manager, it's not a yellow exclamation point at all - it's a black exclamation point on a yellow background. The yellow background is triangle shaped in Windows 7 and Windows Vista and a circle in Windows XP.