Single red LED

After starting up my machine for the first time, I noticed the graphics card (ASUS Radeon 6970 2GB) had a single red LED lit up and there was no signal being picked up by the monitor.

I tried putting in a different card (5770) which had three green LEDs light up, but still no signal.

What I need to know is; does the single red LED indicate insufficient power and/or GPU failure, or is there some other factor at work.

My motherboad is a Gigabyte P67A-UD4-B3 and my PSU is a Corsair HX-650.

For starters make sure that the monitor is set on the right input source, DVI,15pin Dsub, HDMI etc.
You can do this with the on board display on the monitor. We need to make sure that the Video card and the monitor are speaking the same language .

My monitor automatically scans each port for an input and I tried it with another monitor, on the right input, to no avail.

Is the red LED a cause for concern?

i used to get a similar issue with my hd4850, check your manual, it generally tells you what each led means and how to troubleshoot it

The card didn't come with any documentation.

Fixed. Move along.