After you install Windows Vista Service Pack 1 (SP1) on a computer that is running Windows Vista, you experience one or both of the following symptoms:

•	A device driver is not installed, and an exclamation point (!) appears next to the device driver in Device Manager.
•	A device driver appears to be installed correctly in Device Manager. However, the hardware device does not function correctly.

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This issue occurs because Window Vista SP1 updates system files and some device drivers to help improve device reliability. When you install Window Vista SP1, the service pack installation process may reinstall some device drivers at the end of the installation.

Note We recommend that you install the latest drivers for your hardware before you install Windows Vista SP1. When you do this, you can help prevent the issue that is mentioned in the “Symptoms” section.

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To resolve this issue, use the following methods in the order in which they are presented.

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Method 1: Determine whether the device driver is found in Device Manager

To do this, follow these steps:

1.	Click Start, type Device Manager in the Start Search box, and then press ENTER.
2.	If the device driver is not found for a device in Device Manager, an exclamation point appears next to the device. If an exclamation point does not appear, and if the device does not function correctly, go to Method 2.
3.	If an exclamation point appears next to the device driver in Device Manager, you can use Windows Update to scan for a device driver. To do this, follow these steps: a. Click Start, click All Programs, and then click Windows Update. If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation. b. Click Check for updates. c. To determine whether updated drivers are available, click View available updates. If updates are available, click the driver that you want to install, and then click Install. If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.

If Windows Update cannot locate the required device driver, contact the device manufacturer to download the latest device driver for Windows Vista. For more information about how to do this, see the "More Information" section.

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Method 2: Uninstall and then reinstall the device drivers

If the device driver appears to be installed correctly in Device Manager but the device does not function correctly, manually uninstall and then reinstall the device drivers. To do this, follow these steps:

1.	Click Start, type Device Manager in the Start Search box, and then press ENTER.
2.	In the Device Manager dialog box, locate the hardware device that is not functioning.
3.	Right-click the device, and then click Properties.
4.	Click the Driver tab.
5.	Click Uninstall.
6.	Make sure that the Delete the Driver Software for this device check box is cleared, and then click OK.
7.	In the Device Manager dialog box, click the Action menu, and then click Scan for hardware changes. You should receive a message that states that a hardware device is being installed and that the uninstalled device is now present in Device Manager.
8.	If the hardware device driver is not installed, use Windows Update to scan for an updated device driver. To do this, follow these steps: a. Click Start, click All Programs, and then click Windows Update. If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation. b. Click Check for updates. c. To determine whether updated drivers are available, click View available updates. If updates are available, click the driver that you want to install, and then click Install. If you are prompted for an administrator password or for confirmation, type the password, or provide confirmation.

If Windows Update cannot locate the required device driver, contact the device manufacturer to download the latest device driver for Windows Vista. For more information about how to do this, see the "More Information" section.

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For information about how to contact hardware and software vendors, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.

For more information about how to troubleshoot audio problems that may occur after you install Windows Vista Service Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:

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