My Dell Inspiron 5150 suddenly had a black screen with a blinking white light in place of the usual Windows XP screen. I called Dell, who told me my warranty had expired five months ago and refused to renew it. They, instead, offered to sell me a new motherboard for $600. Yikes- that's nearly a brand-new computer!
I got in touch with Nelson Computers, who had refurbished parts that were less than half of what Dell wanted to sell me. They said they were in perfect condition and would have no trouble repairing the notebook for me. Low and behold, two days after handing over my computer, it worked perfectly. I was charged for the motherboard, and $45 installation fees - a really good bargain. Four months later, and my laptop works as good as when I first purchased it.