PC won't boot after routine cleaning

22_sas

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Nov 25, 2011
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Guys, today I agreed to clean my cousin's PC. It was a regular clean which I've been doing on my PC for years - took off the side cases, used a vacuum cleaner and a microfiber cloth for removing the dust. The only electrical component that I had to disconnect was the case fan, nothing more. So after finishing with the cleaning, we started the PC. Unfortunately, nothing had appeared on the screen (the fans were working). I thought that I probably disconnected something while cleaning so I checked the condition inside the case in case a reseating was needed. However, everything was fine. After some unsuccessful tests and readjustments I decided to start the PC with the onboard GPU. Everything seemed to be fine, windows booted without problem (Note that the external GPU has been connected to the mobo all the time). Of course, that highly decreased the number of the possible culprits but so far I haven't managed to find the actual one. I'll be grateful for any suggestions and/or solutions. Thanks in advance!


Specs:
RAM: 4GB DDR3 Kingston
CPU: Intel Pentium G840, 2.8GHz, 3MB Cache
GPU: ATi Radeon HD7750
HDD: WD Caviar Blue 500GB, 7200rpm I guess
PSU: 550W
 

22_sas

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Nov 25, 2011
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18,510
I haven't disassembled it and it seems it is firmly seated in the slot. It doesn't have any power cables.

EDIT: A thing I've noted: When connected to the external GPU the NumLock is constantly flashing. It turns on for around 2 seconds then goes off and that's all over again and again. You can turn it off/on (including CapsLock) when it's at "ON" phase.
 

22_sas

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Nov 25, 2011
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18,510
UPDATE: OK, what I didn't mention is how I had managed to boot up Windows with the onboard GPU. At first, what appeared on screen was just the BIOS, then POST screen then the PC restarted and all that repeating. In order to start it, I had to press ESC and then pick "Windows without Loader" as an option. I've just noticed that the same NumLock behaviour is present so I repeated the same procedure for starting Windows while connected to the external GPU. Of course, I couldn't see anything but I managed to do it. I had all indications that can confirm it - intro sound, Skype, shutdown sound. So I don't know guys, if this info might be helpful to you in some way.

Ps. Sorry for double posting but I thought it's important to mention it separately.