cd drive not available

Currently we have two users on this computer. We have a solitaire CD in the cd drive. When we turn the computer on and whoever logs on first gets the Solitaire CD on their desktop. On the other users desktop the icon is blanked out and when you click on it, it says it is not available, check the path etc.   On the "my computer" page, if you are the first one logged in , you can look at the cd etc and it is there, however, if you go to the other user and check my computer, it says "Drive I is not accessible,Access is denied".   We both used to be able to access the cd and I don't know what changed or what casued this problem.  It shows that the solitaire cd is in the drive, but not accessible.   Any suggestions, ideas would be greatly appreciated....   Thank you for your time and help.........    Bob

Running Windows XP Professional, with two disk drives, one is a cd drive and the other a dvd player burner.