Am I screwed? Can I upgrade my GPU to a GTX 980 Ti or am I stuck with what I have?

[simonz93]

Hi guys
Total noob in PC, just opened one for the first time in my life. I have a prebuilt HP envy phoenix 860-019, here's the specs http://support.hp.com/ca-en/document/c04799759

I'm looking to upgrade my current GPU (GTX 960 that came with the PC) to a Evga GTX 980Ti or Asus 980 Ti Strix, and also replace the crappy default PSU and cooler.

However I was badly surprised when I opened the case. It looks like this.

First of all, it seems very packed, and there is barely any place to fit a GPU. The case itself is only 14.5 inch in length.
And that leads to my second concern. Why is my GTX 960 like this?
http://i.imgur.com/MHi1U2e.jpg

Is this how they look? Anyway that's not what how I pictured it after seeing a bunch of videos replacing/installing GTX graphic cards. This one doesn't have the external case and it looks much smaller than usual GTX GPUs.
So my main question is, can I upgrade the GPU at all? It seems there is simply no place to fit a 10.5 inch GTX 980Ti in there.

Guys please enlighten me, Thank you so much!

 

[bystander]

Actually, I've upgraded motherboards and full systems without losing my OS on my last two builds (I do not recall about previous ones, as it has been many years). I just made sure to uninstall my motherboard drivers before I made the switch.

 

[cst1992]

I have read that porting the OS on a new motherboard causes blue screens.