I think i had that once when i forgot to plug in the extra power connector to my graphics card.
Although i noticed in your other thread that you have 2 different makes of ram running, might be an idea to try with just 1 stick until you get a new matched kit.
Use CPU-z (can be downloaded easily and its free) that will tell you your mobo make, you'll need the main board tab, also what make gfx card?