After cleaning the asus x75vb laptop, it does not see additional 4GB RAM. What to do?

Question

ASUS

After cleaning the asus x75vb laptop ( rozetka.com.ua/asus_x75vb-ty017d/p287951/) , it does not see additional 4GB RAM. There is one for 4GB built into the motherboard - you can see it, the other was purchased for 4GB by Pioneer Memory.
I really need a RAM because I'm doing graphics, plus I'm playing on a laptop, which is not unimportant for relaxing.

Answer 1

The master who cleaned it says that there is either a problem in the motherboard or the slot itself has burned out, since the RAM is working.

Answer 2

Open the laptop again, insert the memory normally.

Answer 3

Make sure the memory is in place. Maybe it's already been stolen.
Check the BIOS setting for Memory Remapping Feature or something similar:
DRAM Over 4G Remapping
H/W Memory Hole Remapping
Hardware Memory Hole
Memory Hole Remapping
Memory Remap Feature
Memory Remapping Feature