Alpha, flashes yellow

My alienware was "fixed" by Dell after it stopped working a few months after purchase.  Then about three months after the manufacturer's warranty was up, the same exact issue happened.  I have replaced the CMOS battery.  Still doesn't work.  Very unhappy with the "service" that I received from Dell on this.  I spent over $500 for something that has barely worked since it's purchase and now they want me to pay $100 just to diagnose what I know is wrong?  Come on, that's just poor customer care.  Has anyone had any luck going through Dell with this or does it just end up costing you a lot of money because you have to buy a diagnosis and a brand new motherboard from them?