When you try to install Windows 2000 from a USB optical drive, you receive a message similar to:

Insert Disk
Please insert the floppy disk labeled 'Service Pack Y CD' into drive X: and then click OK.
You can also click OK if you want files to be copied from an alternate location, such as a compact disc.

NOTE: The message occurs in the GUI part of Setup, after the initial restart. Instead of floppy disk, the message should use compact disc," "CD," or "DVD".

When you press OK and the Browse button, the USB optical drive is not available, and Windows Setup cannot find the Setup files.

To workaround this behavior, disconnect the USB optical drive from the computer when the Insert Disk is displayed. Then reconnect it and wait 30 seconds before pressing OK. This should allow Windows 2000 Setup to find the USB optical drive.