Is it possible to upgrade a pre built pc?

[HiDood]

A friend of mine is changing the graphics of his asus mini pc. Is it possible? Also, we are changing the case of it. But is is possible? Because that motherboard is sure weird. The pcie slot is at the bottom

 

[Im_Infinity]

A friend of mine is changing the graphics of his asus mini pc. Is it possible? Also, we are changing the case of it. But is is possible? Because that motherboard is sure weird. The pcie slot is at the bottom

without a doubt you can upgrade anything just make sure you do your research before buying new parts to make sure there compatible