To add on to what I said above, I went to your motherboard manufacturer's site and read through the RAM compatibility list Compatibility List
for the 790fxta-ud5 mobo; it seems that the RAM that you purchased is not supported at all.
I had the same issue. I assumed that because the motherboard supported 4GB sticks at 1066mhz that the G.Skill Ripjaw 4GB would suffice. That is not the case. I bought the stick because it was cheap; this is one of those situations when that's not a good idea.
Your best bet is probably get an RMA from whomever you purchased it from (newegg.com, for example). Fill out the RMA request and put that the RAM wasn't compatible. I'm going to warn you now, you'll most likely have to pay a re-shelf fee, since the RAM is most likely working just not with what you purchased (which is the customer's fault).
Edited by Mr.VisualBasic, 25 June 2010 - 11:32 AM.