Windows XP SP1 supports ATA-133, but ATA-133 devices are NOT enabled by the installation of SP1.

A service pack does not reinstall devices. Since ATA-133 devices were NOT supported prior to SP1, you must update the device driver for the IDE Controllers:

1. Right-click My Computer press Properties.

2. Select the Hardware tab.

3. Press Device Manager.

4. Expand IDE ATA/ATAPI controllers.

5. Double-click the primary IDE channel and then select the Driver tab.

6. Press the Update Driver button.

7. Select Install the software automatically (Recommended) and press Next.

8. Follow the on-screen instructions.