Components to upgrade a young gamers rig

Hello everyone.

Story time!

I often receive emails and PMs from members of the swec community and social media from folk who want me to build them the best looking PC for little to no budget. Often due to time constraints and kr/h I only take commissioned jobs from large companies such as ASUS, Phanteks, be quiet! etc.

However, a young lad by the name Jonas contacted me recently asking if I could take a look at his PC for any possible upgrades. He had saved up his weekly allowance until he thought that he might have enough for a decent upgrade from his current PC, an old style Lenovo with i3 6100 CPU, a 3.5" HDD and a GT 720 with a budget of 4000kr.

He is just after a GPU upgrade as he wants to play everyone's favourite game Fortnite, but wished if there was any budget left over to have a new chassis with window, and RGB.

Now, we all know that performance should take precedence over aesthetics. but since Jonas wants to be part of the building process and learn about how his PC works, it would be great to surprise him with some nice looking parts as well.

So with this said, what I am after are the following.
1. GPU more powerful than his current GT 720. an Nvidia GPU like GTX780 and higher would be ideal. Preferably blower style cooler if possible.
2. SSD with capacity of 500gb for OS and some games.
3. Chassis with window
4. PSU
5. Motherboard to suit i3-6100 CPU
6. Better performing CPU

Number one priority here is to upgrade GPU and install SSD. I will spend the time to reinstall his OS and games before we do the upgrade process. Anything else will just be a bonus!

All suggestions are welcome, so just let know what you have to sell. Photos of his current rig are the ones displayed in this advertisement!