1) What is new or different since the last time everything worked properly (ie, new hw, new sw, virus, error, etc)?
2) Hard Drive Diagnostics:
Run hard drive diagnostics: http://www.tacktech.com/display.cfm?ttid=287
Make sure, you select tool, which is appropriate for the brand of your hard drive.
Depending on the program, it'll create bootable floppy, or bootable CD.
If downloaded file is of .iso
type, use ImgBurn
to burn .iso
file to a CD (select "Write image file to disc" option), to make the CD bootable.
For Toshiba hard drives, see here: http://sdd.toshiba.com/main.aspx?Path=ServicesSupport/FujitsuDrivesUSandCanada/SoftwareUtilities#diagnosticNote
: If you do not know how to set your computer to boot from CD follow the steps HERE