We have a Dell Latitude 600 laptop that hasn't been used in some time. My wife was gonna give it to someone so she was gonna take off anything that she had on the computer. Upon booting up the message "Invalid system disk, Replace the disk, then press any key." There is no disk in the floppy drive, which is a drive that can be taken out and replaced with the CD ROM drive. I've tried rebooting without this drive inserted to no avail. Any ideas of what may be wrong and how to fix it? Thanks.