No video output from computer any ideas?

i just finished building my computer and everything seems to start up fine but i am getting no video output also my fan on my videocard is coming on i also tried the onboard video with the card disconnected so...any ideas?|||In general, as a 'safety' feature, a computer will not display a graphics output if something is not connected correctly.



Check your connections (a favourite with the older style IDE connection for hard drives or floppy drives was people connecting them upside down.



Go over each of the connections, check your RAM is inserted correctly, and the same with any expansion cards. Having attached the heatsink to the processor you don't want to remove it if you can help it. Also check under the motherboard for any possibility of short circuiting (ie a mounting post that does not match up with a mounting hole in your motherboard).



What you may have to do is remove all components and connectors except the CPU and RAM and start again, connecting one item at a time.



If when you have just the CPU and RAM connected (and of course the monitor) if you are still not getting a signal, you may have to remove the CPU heatsink and check that the CPU is seated correctly. If you do remove the heatsink you will have to clean the heat transfer paste from both the CPU and the heatsink (be very careful with this, there are many guides on the Internet for how to do this safely and I can't take responsibility for your actions with your equipment), then apply new heat transfer paste. You should never re-use the paste that is on the heatsink as you will not get a good transfer again and you MUST NEVER run the computer without heat transfer paste between the CPU and the heatsink.