If it boots, try to clone that hard drive as soon as you can. It might be starting to fail. If it has a USB port use a sata to usb adapter, and clone it with Hiren's Boot CD (my recomendation, as it has plenty of tools you can use (Acronis True Image, etc.) and even a lot of hard disk utilities (partitions, MBR, data recovery, etc.).
If you can't boot from a CD, or it does not have a USB 2 port, take out the disk and use another computer to clone. I am guessing it has an IDE hard drive, so if you decide to go this way you will also need an IDE to USB adapter.
After cloning (to a SSD presumably, currently not very expensive and much more fast and reliable), you can use a IDE to Sata interface adpater to install it on your scope!