i have a dell inspiron 1521 and about a month ago or more when i started up my laptop the cd-rom drive opened unexpectadly. a month or more later it did it again after i started up and connected to the internet after about ten minutes. i have ran virus scans in between these two times and have found nothing so im not sure if it is a drive error or virus. my homepage has not been hijacked. also, if this helps, i don't automatically connect the internet but instead put the password in all the time.

See if this helps:

http://www.sptimes.com/2004/07/19/Technology/Removing_downloading_.shtml

Scroll down to "Keeping CD-ROM tray closed".

If you can't determine what causes the drive door to open, as a workaround you might try using an application that "locks" the door. See for example:

http://sourceforge.net/projects/cdrom-lock/

http://www.cd-eject-tool.com/