Diablo 2 Expansion not seeing CD

[Joyride]

If I play the expansion to Diablo 2 for a while then quit the game and come back later for some reason the game won't recognize that I have the disk in the drive still.

The only way to play again is to restart my computer

I have the latest version and both the Diablo 2 and expansion pack disks are original disks and not copies.

I have WinXP Pro if that helps