No Signal with hd 6670

Hello, So I am having trouble with a new hd 6670. Went to start it up the other day and had no picture, just get the no signal message when i plug in a dvi or vga cable. The video card did work for about 7 days. every thing turns on fine. the fan on the video card still runs. computer beeps for the bios still. If i hook up the vga cable to the on board graphics i do get picture.

I am about lost what to next. So far i have tried un-installing all the amd drivers and reloading the drivers after reboot before and after disabling everything (just get message saying no video card found)

tried to boot in safe mode and use driver cleaner to delete all the nvida drivers and disable the on board graphics.

went into bios and disabled on board graphics and made primary display the pcie slot.

but still does not recognize the pcie video card and went back to onboard graphics after reboot.

I thought it might be the hd 6670 so i ended up returning it and getting a new one and a new one but still same problem.

Also reformatted my comp and still same issue.

I did just find my old geforce card but have not had a change to check it since i had to go to work before I could try it. So i know if that does not work it chances are the pcie slot is bad. but if the geforce card does work I dont know what else to do to get the 6670 to work. or is it possible the psu is just not good enough to run the 6670?

my specs are:
windows 7 home prem 64-bit
Intel Pentium E2220 / 2.4 GHz
4 gb ram.
hd 6670.
480w psu (the one that came with this LOGISYS case)

got issue resolved after a second reformat.