Golden tee complete red board (no signal)

[Schmitty2121]

When plugging in and starting my game, I get no signal on the screen.  Upon review, I noticed that the board and fan would start up for 3 secs than shut off immediately with the same no signal on The screen.  I purchased a new power supply thinking that may be the problem, hooked it up, board now stays on, fan is moving- although seems slower than before-- still says no signal on the screen?  The board has 2 green lights, one steady and one flashing... What's my next step?  I have heard the hard drives go bad and the video card?  What's your opinion? Can I buy any video card from best buy?
Unit was working fine 6 months ago-- every now and then when I started it, I would get no signal. Turn of and back on game worked... Now every time no signal.. Hope this is enough info!! Thanks Matt"