Question PC worked before changing thermal paste, and now it doesn't

[Luka858]

I had this pc for 4 years, and cleaned it from dust every year. Some times I had to reset bios, but that was due to unsuccessfull overclocking, but after returning everything to default it worked perfect.

This time I decided to change 4 year old thermal paste on my Ryzen 3 2200G (it works on Radeon Vega 8, no dedicated GPU). I did it perfectly, no paste in socket, no broken pins, grounded my self few times to prevent electric discharges, connected everything as it was.
I connected PC to peripherals and pluged it to the power outlet, at that moment blue LED (next to power button) lighted imidiately, even the pc in turned off. I wait for few seconds and turn it on. It lights BLUE and RED LED, loads bios perfectly, but has problem with loading Win 10, it shows blue screen with options like: do system recovery, reset system, etc. And I turned off and on PC several times and tried every of options. It did't help.
(I didn't want to reinstall system, or put another one because I would loose all game saves and some files in C partition)
Then I powered it off, removed powercord, reset bios with jumper, remove the battery on MB for almost an hour, put it back. Wait few minutes, give it power again and press power button.
NOTHING. All drives and fans spins, but no picture even after 10 minutes. I also conneted a working beeper, and it didn't beep even once. This time BLUE LED lighted again, but RED (for drives) didn't (probably couldn't get into bios, so it hasn't come to checking on drives yet).

Then, I removed one by one component to see if something is preventing it from boot (all components except PSU, CPU, MB and RAM). Nothnig changed.
Then I try replacing and moving RAM to diferent slots, same again: no picture, no beep, all fans and drives spins up. Maybe it's PSU, changed it with other working one, again no changes.
Then, once again I removed the coller and CPU to check if I maybe messed up with thermal paste (but then it wouldn't work at first when it turned on and bios worked, and Windows 10 had a problem, not MB). So after assuring there's no paste inside socket, turn it on, no change once again.

PC specs:
- Biostar A320MH ver 6.0
- Ryzen 3 2200G
- 16 GB @2666 MHz GEIL (2x8)
- 200 W Rhino PA500 PSU
- 120 GB Patriot sata III SSD
- 1 TB Western digital HDD

= In conclusion: when press power button it spins all fans and HDD, BLUE led lights and RED led does not, it shows no picture at all, it does not beep.
= I suspect it's MB or CPU, but would rather say it MB, because it had sevral issues in past with audio ports. But now even if it doesn't give any picture it still gives power through all USB ports and sipn up all the fans, so Idk. It might be cpu because there's no picture on any connector (HDMI, D-sub, DVI-d) and graphics is integrated. I hope someone can help..

 

[vishvajit]

It looks like you've tried a lot of troubleshooting steps, which is great! Based on your description, it appears that your PC is not showing any video output, and it's not beeping, even though all fans and drives are spinning. This can be indicative of a few different issues, such as a malfunctioning CPU, GPU, or motherboard. Since you've tried swapping out the PSU and other components and still haven't seen any results, I would recommend further testing with a different CPU or motherboard to determine if either of these components are the root cause of the issue. If neither of these components fix the issue, then it's possible that the issue lies with the GPU or another part of the system that you haven't yet tested.