Today I tried to rebuild an old system I had once, and it doesn't work. It's a Pentium 100@120 with a 4 MB video card and 24 MB RAM. When I turn it on, it doesn't post. I know it's not the video card because that works on other systems, or the clock speed because it worked before. I tried two other CPUs with it and nothing worked. Is the motherboard dead? The motherboard has a little red led on it and it still lights up when I turn it on.