This problem can occur if the data value of the Drivercachepath value name has been changed.

To resolve the problem:

1. Use Regedt32 to navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Currentversion\Setup.

2. Double-click the Drivercachepath value name, a REG_EXPAND_SZ data type, and change the data value to %SystemRoot%\Driver Cache.

3. Shutdown and restart your computer.

4. Install SP2.