So, earlier today my computer was working fine. I know not to clean the inside with a vacuum, but I was vacuuming earlier and was pulling dust off the back at one point. When I finished cleaning, I connected my computer back up (I've had it for about 3.5years, worked fine before) and the screen gave me the no input detected bit. Everything powered up, but nothing seems to get going. I can't get to any screen whatsoever. As of right now, I'm figuring it's either the motherboard or the power supply. When i boot up, I can hear the HDD's slight hum, the CPU fan works, the video card's fan works and the light on my sound card turns on, but I'm not getting the screen. I found this website doing a google search for a similar problem as mine, but the thread was about as old as my computer so I figured I wouldn't get any new help from it. I'm figuring something shorted when the metal touched the back of the base, but how can I distinguish whether the problem comes from the motherboard or the video card? So far I've checked all my connections inside, taken out the ram and moving the slots around, tried the video card in different PCI-E slot, changes slots on the sata cables. I also took out the little battery on the motherboard for 5 minutes and put it back in. None of those worked. This seems like the right section for this, if not, I'm sorry in advance. Also appreciate any advice anyone has.