When I boot up my computer it says Invalid System Disk Replace the Disk and then press any key. I have an external floppy drive so it wasn't even connected to the computer when i booted up. Please help!! Thanks!

Try to find out if your pc recornice the harddisk in it, if your harddisk is spinning up when powering on. If cables are all plugged in correctly, otherwise if the disk is found by the bios, make on another computer an win98 bootdisk boot from it and look if you can see the disk and the files on it, if you see the files, and your OS was/is the same as the bootflop is made on, type in: sys a: c: if you can't see any files anymore and you are sure bios settings are correct, cables are ok and there's no floppy or other bootable device connected than there's a change your HD may be crashed. Try to plug your harddisk into another computer and see if it's detected over there!

This is a Sony Vaio Laptop. How do I check to see if my hardrive is working on another computer? thanks

even when u plug the floppy but without disk in it? try to change bios boot sequence

Boot with a startup disk ~for your O/S~. As someone above stated, do a dir c: at the A:\> prompt. If you can get a directory of the drive, the boot record or boot files may have become corrupt. Try typing sys c: (from the A: drive). You should see SYSTEM TRANSFERRED. Try booting normally. If that fails, try booting with the start up disk again, and type; fdisk/mbr at the A:\> prompt. Try booting normally. Post your results to this thread/topic.

If the disk has failed then try www.computer-recovery.com they can recover any important data that you may have on the failed drive