Help!! what should I upgrade ?

As is always the case with cheap pre-built gaming PCs, the GPU is the weak link.

Newegg has the Zotac GTX 1050 Mini on sale for $100 right now.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814500412&cm_re=GTX_1050-_-14-500-412-_-Product

Fortunately there's some great deals on PSUs right now, like the Corsair CX430 for $16 at Newegg.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026&cm_re=CX430-_-17-139-026-_-Product

Total would be $87-$103, depending whether your current PSU is adequate.
 

CTurbo

Pizza Monster
Moderator
Solution

Actually not same price. ASUS Strix 750 Ti is $87 right now. I hadn't noticed the Zotac Mini is on sale for $100 though, which is a better deal, so I edited my post.

Pretty sure the 1050 will run on the CX430 I posted too.
 

I was just offering lowest overall price, we don't even know yet what he can afford up front, as he's not said. And I'd wager to bet that CX430 is a lot more reliable than what the system has now.

At the very least, $126 is still less up front than your $139 suggestion, with the bonus of getting $20 back.