I have an XPS 700 with Vista Ultimate on it. Whenever I shut off the computer and go to turn it back on, it locks itself on full fan speed and there is no POST. Then when I manage to get it working by plugging and unplugging various devices (HD's, PCI cards), it works fine. Then when I restart it, the computer starts beeping, and the codes on the front are (3,4). I realize this is a memory error, but if it genuinely was, it wouldn't turn on at all would it?