Over the past month, my dell dimension 4550 has been doing some strange things. Every few days I would have to spend at least 10 mins restarting my computer until it agreed to boot. The monitor says that there is no video imput, and the lights on my keyboard would not light up. (Just as if the computer wasn't on at all) The strange part is that after unplugging and reattaching the cable in the back of my monitor a few times, windows would eventually decide to run. I know its not a problem with the monitor or cable because i changed monitors and the problem continued. Over the past 2 weeks this problem has been happening more and more frequently. As of right now, it will not boot at all (I am typing this on my mom's laptop) If anyone has any advise, i would love to hear it. Thanks.