[Budget] <RM3k

[Purpose] Gaming, movies, occasional graphics work

[Hardwares that will be re-use] No

[Monitor resolution] 1920 x 1080

[Games & softwares that use frequently]  Game - Witcher, The Forest, Skyrim etc, Others - Sketchup, Gimp

[Personal preferences] Rig only no need monitor and peripherals

Are the suggested parts compatible or require trial and error in building? Preferably no tinkering, noob here.

Also, I have an unused Win 7 oem license. Can I install on the new rig myself?

If custom build need a lot of trial and error, I might consider the pre-built Dell ones albeit shitty and less value for money. Thoughts?

Inspiron
6th Generation Intel® Core™ i5 Processor
8GB Memory
1TB Hard Drive
1TB Hard Drive
NVIDIA® GeForce™ 730 2GB GDDR3.

Alienware Aurora
Intel® Core i3 Processor
8GB memory
1TB hard drive
NVIDIA® GeForce® GTX 950 with 2GB GDDR5.
P/s current custom rig failed to load. Casing light is on but not booting up. No idea if hdd or psu failure. 6 yr rig, psu changed 2 yrs ago (Hexa 550 if not mistaken).