Were you able to run the diagnostics by tapping F12 at boot?
There are two ways to go about saving the data on the hard drive. The first is to remove the drive and attach it to another computer either internally or externally using an USB external enclosure or adapter. like this. The external enclosure would depend on whether the drive is SATA or IDE.
The other option is to burn a small linux distro. I recommend Puppy linux. You can download version 5.2.8 here. You would need to burn the iso using Windows 7 by double clicking the file or using a program like Imgburn. You said you cannot boot from CD but I would try using the F12 option to get to the boot menu and see if you can boot a CD using this method.
If does not work, try booting Puppy from a USB flash drive. Download Rufus and in the dropdown box, select iso and browse to the iso file you downloaded. Check quick format. Anything on the drive will be deleted. Attach the flash drive to the computer. Boot up the computer and tap F12. You should get the option to boot the flash drive. After Puppy boots, you should see the hard drive in the lower left of the desktop. Click it once and the FileManager will open. Attach another USB flash drive to the computer. A USB icon will appear on the desktop. Click it once and another FileManager window will open. Then transfer the files by dragging from the hard drive window to the USB window. A dialog will open asking whether to copy or move. Select copy. Here is a guide explaining the process.