Now I'm not sure when the blue text stating that "only AM2+ sockets are supported" appeared (must be recent, I guess). But the thing that makes me believe it will work is the fact that the current processor is an AM3 CPU (AMD Athlon II x2 220). Will this CPU work on my motherboard?
That motherboard is Socket AM2.You might be able to use the AM3 with a BIOS update but i think the voltage pins are way different with AM3 than AM2.
I think you'd be better off going with a new mobo.
Also, if your going for a Phenom quad core go with the 925 not the 840.The 840 isn't acutally a Deneb so it doesn't have the L3 catch.Your better off going with a Athlon because it's practically the same thing and save some money.