Our Dell OptiPlex (Windows 2000 Professional) has suddenly stopped working. 

 

After being powered up, the hard drive light blinked for couple minutes while making a clicking sound like it's stuck.  After couple minutes, the light indicator went dark.  At this time, I can open and close the CD drive, and the monitor suggested that the hard drive is at "sleep" mode, although nothing can wake it up. I have tried plugging in different monitor and keyboard when its off.  I can't even to get it boot up with the diagnostic CD. 

 

I have heard that there are problems with the power supply in other Dell computers.  Was the above an indication of a bad power supply??

 

Help, and thanks!