If gaming is the be all end all, and he wants better graphics performance, then yes, I agree completely. All I'm saying is that you're saying "he doesn't need a new case" and that's true, but the same holds true for a GPU- he doesn't need a new GPU. He wants one. Just like the case.
For people that like to shove their PC under a desk case probably isn't important, but it you like to set it on top then having something you're going to use everyday for years not be butt-ugly is a fine reason to get a case.
Both the case and the APU work just fine. But he wants new stuff, and the case isn't nessasary less important to him then the GPU. We don't even really know what he's using this computer for.
What you're suggesting is equivalent to throwing money in the fireplace. Seriously. No offense is intended, I just really don't think I'm making my point here. He has a computer. We've established that. The computer is in a case. The computer has an APU. He
does need a new GPU, if he wants to game, because a low end APU like what he has is not going to be decent for gaming, even at 720P, in pretty much any AAA title, except the Sims, which it should run swimmingly based on my experience (I run it on my mom's 5150 Athlon APU). He does need a new GPU. But does he
need a new case? No. Does he need a new PSU? No. What the heck for? Those OEM PSUs are usually fairly long lasting, even if they have garbage efficiency. They don't roll over and die after 6 months in most cases. So he thinks the case is ugly/ you think the case is ugly. So what? What you're proposing is taking an unattractive 1989 Volkswagen Rabbit and repainting it and putting a wing on the back of it. What's the point? You're just throwing money at a junker, which is essentially what his PC is. Again, no offense intended. I'm just trying to make a point. This guy has what was probably a $400-500 OEM PC, and you want to spend $60 on a case, $80 on a PSU, $140 on a GPU. That's almost $300. So you're nearly doubling the price of the PC-- to what end? To get a higher framerate in games? When you could pull that off with just over $100 with a low profile 750Ti? Ridiculous IMO. Just ridiculous. He's made his bed by buying OEM, or being gifted OEM, or whatever the case was. Let's not waste money by putting makeup on a monkey. The only worthwhile pursuit here is to improve the performance of the machine, and that can be done for just over $100 with a 750Ti. Case is ugly? Put it under the desk. No sense spending money to make a monkey pretty.
"Nice case. What kind of rig you got in there?"
"A low end OEM mobo with a low end APU"
Doesn't make sense. I'm guessing this is your friend's first desktop, based on the rationale being presented in this thread. All I would say to him at this point is to never take form over function in life. In any respect.
He can take that $300 he has, add another $500, and buy a truly decent gaming machine. Don't let him flush it down the toilet.