I think its telling you it can't find the bootable system that was on your hard disk because that is failing.
Now would be a good time to remove the hard drive and buy the cables to connect it to a laptop or just put it into another PC. Rescue your personal files first then use the system to check the disk for errors.
I or someone else will describe how to do that when you come back and say whether there's any life in the disk once you migrate it.