4 RAM slots but 2 not working

[Msiyana]

I'm having problems with my Desktop PC "HP Elitedesk 800 g1". The motherboard has 4 RAM slots, I was using 16 GBs of Ram (4GB x4) . Up until I had to de-assemble the tower components due to dust cleaning & adding of new Thermal paste. Now only 2 of my RAM slots work, when I insert to the other two that's not working, I hear a beep loop sound that plays two times, then the sound and spinning of the fans start to increase as if it's about to explode.

[WAWood]

@Msiyana 

When you removed the CPU fan and housing to replace the thermal paste, were you careful to ensure that you were (1) wearing an industry standard grounding strap, and (2) the strap was actually grounded to something that would dissipate the static electricity you would pass along to the motherboard when you touched it?

[Msiyana]

No sir. I didn't even know of that.  How can I fix this problem now ? If I insert the other two RAMs on the 2 slots, I get 5 short beep sounds.

[WAWood]

@Msiyana 

You can't -- as any damage is already done.  If you are going to work on PC motherboards, then you need to educate yourself in advance regarding the safety precautions to take.  It is too late now.