I purchased a tower yesterday from someone and he had it hooked up to a 42" tv and it was working perfectly fine. Now my monitor wont detect a vga signal and my tv which is 32" wont detect the HDMI signal. I've moved around the vga cable and hdmi to the onboard and my other video card installed and still nothing. I've completely disassembled the computer and put it back together, i also held down the power button for 30 secs or so with the power cord attached and without it. I also tried doing that for my monitor as well still nothing. The monitor is blank but i know the monitor is good ecause ive tried it on another computer and I have tried other monitors on this computer also.. the monitors stay in sleep mode with the orange light on my power button (usually sleep mode for hp monitors) and when i hit the menu button or select button or even the power button on the monitor it says MONITOR GOING TO SLEEP .. i have no way to run the computer in safe mode to try the f8 function to set it in vga or low resolution... MY OS is windows vista also and as i said before the computer was just working a few hours ago and it still starts up fine and everything runs perfect.