Fatal issue after re-assembling my PC

Hello everyone,

I have an Asus Desktop G11CD-K PC (the K is for Kabylake version) wich i disassembled to clean all its parts (including Graphic card fan, its Processor and cpu fan and by replacing its thermal paste,  and also its front components).

After cleaning:

I did these steps:

1. I assembled it correctly, but to be honest i did not think that i used all the right screws, but i chose it by its placeholder forms and places.
2. i turned-on my PC, i found that CPU fan, Graphic Fan, PSU and HDD worked well, but all other parts did not work, like back-fan, all USB peripherics, no signal to the monitor etc..
3. I tried all possibilities:
   1. Disassembling and re-assembling again many times.
   2. Changing RAM to different slots testing it one by one.
   3. Testing with basic components.
   4. Removing all parts and add it one by one to see if something can make a change but still no changes.
   5. I took out my mobo and test it out of the case but there are nothing again.
   6. I tested my monitor signal sometimes with PCI GPU , and sometimes by iGPU and in the two cases there is no changes.
   7. I pulled out my back-fan (which was not working on the mobo) and i tested it out of the mobo with a 9Volts battery, it worked well.
   8. I checked all my ATX-24 pins PSU voltages with multimeter and with a PSU tester, it gave me the right voltage values.
   9. I reset my CMOS too by pulling out its battery and waiting for 20 minutes, but the issue still existing.
   10. Finally, i plugged my usb mouse and/or my usb keyboard, it lights for milliseconds then it turns-off.

Extra Details:

1. When turning-on my PC: CPU-fan,PCI-GPU-fan and also HDD are turning all well, but all other parts plugged directely on the mobo does not (like usb ports).
2. I used a HDD station to check if my HDD still alive and yes it is fortunately and i was able to recover my data.
3. When cleaning, I used this electronic cleaner liquid. I was not sure but i have a doubt about this step, becasue when reading its manual, it says "it is safe for electronic devices and electronic boards).
4. After all precedent steps, i used also another electronic cleaner after watching this video hoping that it can help me to remove any problem, but this did never also help.
5. Before cleaning, i assured that there is no component attached to the current neither to the PSU, and i harded-reset all capacitors by long-pushing power button for 30 seconds to empty all currents from there.
6. The only thing i forgot here is pulling the CMOS battery from the MOBO. I hope it can not be a cause of a short of something.
7. Remarks: I was obligated to use "contact cleaners liquids" because in my country there is no shop buying compressed air and i wanted to order one from France but they told me it is forbidden because it is flammable.
8. I'm a developer, so I have many basic ideas and knowledge about electronics and hardware but i still beginner, so i can learn and understand anyway..

What i expect to know here:

• What can be the cause of this issue ? is it the cleaner itself or cleaning when the battery is plugged into the mobo? or it could be another thing ?
• If it is the cleaner: is my mobo is damaged now or not? and this can damage other parts like cpu or they are safe so i can use it on another mobo?
• Can i repaire it? or i should just replace it or the damaged parts?
• Can i use my multimeter to check the mobo and/or the CPU at least?
• Have you any other troubleshooting suggestions ?

My first goal in this forum is to learn more than repairing,

so i hope you can help me by answering all my questions.

thanks

Hello everybody again,

I’m really sorry for my late answer, because i was waiting for some bought components (my new case , new MSI motherboard and different tools for PC Building).

I’m really happy to say that i finally solved my problem by re-building all my pc using the old parts (except the prebuilt case and the old ASUS mobo),

now my PC works well with my new build, so that i confirm that the problem was only because of the fried mobo.

Fortunately, none of my other components was damaged :D , so I used it in my new case :))

This is my first PC diagnostic & building experience, so i’m really happy to learn something new and I thank you all because i learnt a lot from all of you :)

here is pictures of my new build: