strike F1 to reboot, F2 for setup utility

I have a 5 yr old Dimension 4300.  Last week, I could not get it to come up after hitting the on button.  I would see the Windows XP logo pass by and then a blank screen stating: "strike F1 to reboot, F2 for setup utility".  If I hit F1 the message just would repeat itself.  There was also a clicking noise in the background.  I tried turning the computer on and off a few times, but no luck.  The next morning I tried a few times and got lucky.  Stupidly I turned the power off when done, and could not get the computer to turn on.  I repeated the on-off maneuver every now and then, and the next day I had success.  I left it on for a day and a half and then accidentally turned it off.  After 3 days of trying again, I finally got the computer on again.  Any ideas?  I have been told anything from  my hard drive is dead to it needs a battery.

 

Thanks for any help