mobo/psu/video card

[[BlackDawg]]

hey i have had my current system for about 9-10 months and all of a sudden everytime i turn on my pc i get nothing on my monitor. the fans are working i changed video cards and monitor still nothing. i am going to buy a mobo and a processor do i need a psu or another graphics card?plz help.

I have a
-Asus A7N8X-X
-athalon xp 1.8ghz(dont know much bout it)
-COOLMAX CR-450B ATX 450W "140mm Fan" Power Supply 115/230 V UL, CSA, FCC, TUV
-Nvidia Gefore FX5700 LE 256MB

 

[[BlackDawg]]

ok so i switched psu with an older one and still nothing i think its the psu