desktop died :(

[Magnu420]

my old faithfull a system built desktop completely died the other
week,but a couple of weeks earlier before dying,it been havin a problem
starting up it used to make clunking sounds when starting up(i use this desktop as a server for my lappy and multimedia box),anyway before the final days of dying the pc was frozed,ie couldnt
log in,so i rebooted by pressing the reset button underneath the main power switch,still nothing happened so i turned it of from the mains,left it
about 10 mins to cool down etc etc,started it up the post screen said it
never reckonised the drives (ive 2 an 80gig which had xp pro on,the other drive was a storage 250 gig drive),then it was a blank screen,so i tried again still said same not seeing the drives then a blank screen,but i noticed the hdd was clicking,so i rebooted again then nothing on screen,no post screen beeps just a blank screen and hdd clicking,so i thought it was the hdd with xp pro on had gone,so i replaced the 80 gig
drive with a 250 gig hdd,made sure the jumper was set right,cable firmly pushed in,even cleaned all the dust up around the cpu,ram,psu,mobo,made sure cpu was firmly seated,turned the pc on, no post screen,monitor saying no signal,power is lightning the pc up ie display is lit up,fans are spinning,dvd drive lites up,it wont boot from a xp disc nor a floppy boot disc no post screen nothing.also ive took the ram out,disconnect the drives,booted up no post screen,took the cmos
battery out for a minuete put it back in and booted up still no post screen or beeps,i did try the psu
ie put a bent paper clip into where the blackwire and a green wire and booted up the fans were spinning

any ideas on this please

destop about 4 years old
asrock mobo
1.6 ghz cpu ?? (i cant remember of hand)
778 gig of ram
it had a 80 gig maxtor hdd but swapped with a 250 gig hitachi hdd (ide)
xp pro was on the 80 gig drive but nothing on the 250 gig
dvd rom
dvd rw
floppy disc drive