I just built a computer and have a ASUS Sabertooth AM3 MoBo and am trying to use a RadeonHD6850 graphics card. My power supply is a 740W one. When I first start the computer all the fans come on and everyone appears to be working correctly but when I try to plug up to a monitor I always get "No Display." I have tried with HDMI and with VGA/DVI on my television as well as a monitor. Any ideas?
Word to the wise: never use a television to do an initial set up of a computer; always use a monitor. I've had to troubleshoot a couple builds that were only giving no display errors because they were being used on a TV instead of a monitor.
I see that you used a monitor too, so that's not the issue.
Does the motherboard you got have integrated graphics? If so, then there should be settings in the BIOS that you have to change to make the PCIe card your default display device.
And make sure the 6-pin connector from you PSU is plugged in to the card.
Also, if your motherboard has multiple PCIe slots, make sure it's in the main one. 9 times out of 10, this means the slot closest to the CPU, but it's possible that some motherboard set it up differently. Refer to your motherboard manual to make sure that's correct.
Failing all of that, if your motherboard has integrated graphics, try running the monitor off the integrated card. Or if you have a spare video card, or one you can borrow from another computer or a friend, throw that in there and see if that boots. If either of those cases works, and you're sure the settings in the BIOS are right, then your card is probably faulty.