Hi @trachawk ,
What is the make and model number of the desktop PC or the motherboard if a custom build?
I assume that the water spilled on the CPU fan, is this correct?
After you have inspected the motherboard and cleaned it properly (see below) here are some checks that may help.
Perform a paperclip test on the PSU to make sure that all the voltage supplies are OK.
Connect a system speaker (example only) to the appropriate header pins on the motherboard if it hasn’t got a system speaker connected already, to listen for any beep error codes that may be heard at startup. It may not be passing POST (Power On Self Test) when starting. The user manual for the motherboard is required to know where to connect the speaker and also what brand of BIOS is installed to know what the error code (if any) means. Here’s a list of various BIOS beep codes that may help
If the PC passes POST is there a separate GPU card installed in the PC or are you using the onboard video graphics? If a separate GPU card and the CPU has integrated graphics and the motherboard supports onboard video i.e. video output connector on motherboard, try removing the GPU card and using the onboard video instead, in case it is a GPU card failure.
To eliminate the possibility that the new monitor is the problem, connect the PC to a TV’s HDMI port and use that instead. Remember to change the TV’s signal input to the appropriate HDMI input connection. If there are still no images then the new monitor is OK. If there are images on the TV, then…..
The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the motherboard’s operating design and could damage the components. The corrosion starts immediately and is ongoing until it is completely cleaned away
First do not try to turn on your computer and disconnect the power from the PSU, so as to minimize any further damage.
Then you need to access the motherboard and clean all the affected parts using Isopropyl Alcohol 99%+ (available at electronics parts stores) to remove all traces of corrosion and water. If possible do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives and is not as effective. If you do have to use it check the label to verify the amount of IPA. The higher the percentage of IPA the better
Here is a link that describes the process. Electronics Water Damage
As always with electronics, especially surface mounted pcb be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board. Remove the shields that may be covering some components as the water may have got in there. The ends of any flex cables and their connectors need to be cleaned as well
Hopefully after you have done all this the computer might possibly work correctly again.
If this process seems too daunting, take your computer to a reputable, professional computer repair service, experienced in liquid damage repair and ask for a quote for a repair. If you decide to do this, do it sooner than later.