If I accidentally leave a floppy in on shut down, on the next bootup I get a message "non system disc (or something like that), remove it and press any key". If the P.C. knows there is a disc which shouldn't be there why doesn't it ignore it? Just curious.
Computers are pretty stupid things really, it looks at the a drive as part of the boot process if it sees a disk it thinks it's a system disk and gets confused when things don't look right, that's where the human being intervines to correct it's stupid ways.