Hp Compaq DX6120 mt Blinks in Red continously when connected on Power

[Robin29]

I have an HP Compaq dx6120 mt which has stopped functioning, When i connect it to Power, it just blinks in Red and continuously before even pressing the Power button.

It happened some time back and finally worked. but now it has repeated it.
Kindly Help

 

[Combat Wombat]

This is an older unit... sometimes if there is a build up of dust ect, it can cause a mobo fault, I would bust the old unit open and give it a good clean out, using compressed air. Sometimes a red light is displayed where there is a mobo fault. But mostly it's a beep...