Import fail, lighting fail, - engine crashes

Lately i have been experiencing bugs in the UE4 Engine (4.16.2)

1st. I make the largest Landscape size 255x255 quads + fill world, i try building lighting but it would always fail to build lighting.

2nd. If i import ANYTHING ( fbx or texture png files) the engine would crash for NO reason.

I have tried uninstalling and re-installing the engine several times and this fatal problem still occurs, i have checked the ue4 community and none of them seem to have this specific problem.

my computer is made up of : Gigabyte 990x gaming motherboard, AMD fx8370 processor, Zotac GTX 1050 graphics card, total of 8 gb of hyper x savage RAM, and Windows 10 64-bit.

I have been trying to create a SERIOUS project for video game development and already have a team ready, but with these frustrating bugs and crashes, i am currently not even been able to import simple things like textures or build lighting for landscapes.
Please I need these crashes to end, or else i may sadly have to go back to Unity3d.