Deminos

Well for starters I built a budget PC (around 500 dollars USD) due to my current income capabilities and now that my income has increased  slightly (mostly due to less expenses now) I wish to upgrade a tiny bit. 
 
Current specs are :  
  
Prrocessor 
AMD Phenom X2 555 BE 3.2Ghz dual core. (99% sure I can't unlock the other two cores in it sadly) 
 Edit: L3 cache 6mb L2 cach 2x 512 kb
Motherboard 
Msi 870a G-54 ( I see this motherboard is used by quite a lot of people but i'm not too sure how good it is compared to the new things out atm) 
 
Ram 
2x  2gb Dual Channel DDR3  Ram 
  
Video Card 
ATI Radeon HD 5770 (Overclocked to 900 mhz by 1350 mhz can go up to 1400 but It gets a little to hot for my comfort.)
 
PSU 
500 watt Corsair  
 
I don't believe I'm forgetting anything to important. I won't be running games over 1400-900 Res. A friend suggested to me that I get a Nividea card and use a program to set it as the main visual card  and then an older card I have to just do the calculations but i'm not sure how that works or if an older card doing the calculations would work out in that. I don't particularly want to Crossfire due to my PSU maybe not being able to handle it as well as my processor possibly bottle necking it, as well as other simple concerns. 
 
              Any help on this will be appreciated  
 
                       Thanks in advance Giant Bombers~   Deminos 

So I recently built a new computer and everything works except when I try to play any games. The card is saying all the drivers are installed and updated yet it won't run a single game I own, when it should. I have no on board graphics just the card. 
System specs 
AMD phenom II X2 555 3.2ghz dual core 
4 gigs of Ram 
64 bit Os   : windows 7 Ultiimate 64 bit 
Radeon HD  5770 
Everything else works perfectly fine but the games, oh the games will not be a playin.

So I got all my parts but the case today, UPS said my case will be coming in Thursday or later. Why me? I want to be cruising at warp speed on video games now!

I had wondered if it used different dimensions, but I figured it was Length and width.  Thank you for the picture, DD 

Yeah since this is the first computer I've built with the help of a few friends I've been worried about the whole fitting issue, as I'd hate to spend a lot on a full tower, they are rather expensive.Thanks Hitman for looking at the case from the inside, that gives me a bit of reassurance knowing it looks like a fit, even though it may be tight.

Well i will have a Ati 5770.. I hope it'll fit.

Alright I'll be hoping, and take your guys words for it. 
Thanks.

Well the dimensions are about an inch in difference on the width. The mother board is an inch wider is why its concerning me.

Everyone that builds computers that I know, says it most likely will, I'm still unsure and would like some more opinions. 
The case :  http://www.newegg.com/Product/Product.aspx?Item=N82E16811147073 
The Motherboard :  http://www.newegg.com/Product/Product.aspx?Item=N82E16813130275 
 
           I greatly appreciate any feedback.