i loaded a dos game on my system. i received the error message that your computer may have a virus. then i received the message that my master boot file has been altered. when i received the system, everything was loaded on the hard drive with no back-up install disc to go with it. anyway, now since this has happened my cd-rom drive does not even boot-up. the drive letter will not even show on my file screen. i have gone into run...d:\install or setup. someone said i needed to add a command line to my config.sys file. i have no idea what kind of command line to enter. i have purchased a pc handbook that gave me ideas, but they did not work. can one of you please help me find an answer as to how to solve this. i really would like to have my cd-rom drive back on my computer. thanks in advance for your help.