This site is being deprecated.
Please see the official X‑Plane Support page for help.
Once you have reinstalled X-plane into a Windows environment consider purchasing the USB key through the following link, http://www.x-plane.com/store/desktop/x-plane_10_home-use_usb_key/ . In doing so, you don't have to use/insert Disk 1 and run the risk of damage to the disk at some stage when you run X-plane. Your boxed set will remain in a pristine condition.
Like you I have the boxed set and use the USB key. The key is mounted on a full time basis. The key has a hole in one end to enable a security lead to be attached for attachement to your PC(?). As the key is small and by attaching it to your PC it lessens the risk of losing it if accidently knocked out of or removed from the USB connection.
This site is no longer being actively maintained.