Sounds like it does not recognise your hard drive as a system disk. Or does not recognise it at all. What is your operating system. You can use a windows 98 start disk as a boot disk. will will start the PC in dos mode.
Have you got a CD or a floppy in one of the drives? It sounds as though your computer is set to boot from one of those drives first rather than the hard drive. If so, take the disk out and with a bit of luck the computer will then boot from the hard disk and all will be fine.
Now we know. Go hear for a floppy disc click the Tenth file down. click here after download Put a Floppy disc in the computer, and double click on the File you downloaded. it will make a Boot floppy to start your computer and get it to A:\>
When it's at A:\> type C: press enter. at
C:\> type WINDOWS press enter. at
C:\WINDOW> type SCANREG /RESTORE press enter. you should get a Restore list of Registry dates of when it last booted OK. Now use arrow keys to scroll and put a old date back then press enter. Note the space before /RESTORE