For Windows 7 and Vista:
To close a disc session manually
Open Computer by clicking the Start button and then clicking Computer.
In Windows Explorer, click the disc burner drive, and then click Close session on the toolbar.
The session will be closed, so the disc can be used in other computers.
You can change the close session settings for both multi-session and single-session capable discs by doing the following:
Open Computer by clicking the Start button Picture of the Start button, and then clicking Computer.
Right-click the disc burner, and then click Properties.
Click the Recording tab, and then click Global Settings. Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Do one or both of the following in the Global Settings dialog box, and then click OK:
If you don’t want to automatically close the session when you eject a single session-only disc, clear the Single session-only discs are ejected check box.
If you don’t want to automatically close the session when you eject a multi session-capable disc, clear the Multi session-capable discs are ejected check box.