operating system

if no disks are in the floppy drive or cd rom drive when you start it up, either try to reinstall the operating system, or take it to someone who can

That message usually refers to the fact that no bootable floppy is in the drive, or the harddrive has failed and it it trying to find a device to boot on. If no floppy in drive, probably a dead hdd. Check to see if the computer identifies it in cmos.

Vickie

If you have multiple harddisks, make sure you boot from the correct harddisk. This can be chosen from the bios setting.
As in the case that your computer cannot detect the harddisk in your IDE slot, the harddisk probably went dead. ;)