If you are getting throught the POST (power on self test), then to a blinking screen, it is most likely that your hard drive has failed.
To test the rest of your computer's components, get a CD that is bootable, such as an OS installation CD, or a Linux bootable, and put it into the CD rom and boot the computer. if it boots to the CD, then your computer is OK, and it is a problem with the hard drive.
If you have important data on that drive, sometimes even if the hard drive fails, you can still access it by removing the hard drive and plugging into another computer via a USB interface.
did you do as suggested and get the linux boot cd to see if you computer actually works .a learning curve for you maybe ,but ,its that or a computer repair shop / http://www.puppylinux.com/cd-puppy.htm
the idea of using the disk is to ruel out the hrddrive ,the disk will load linux into RAM ,so if its not loading its something else .like ram or motherboard .
remember when i refer to harddrive i mean the drive inside the computer /laptop