Unable to power on for more than a few seconds

A few months after purchasing my 17" MSI, I spilled sparkling water into its vents (while powered off). When I attempted to power it on that evening, it would only come on for a few seconds. (Lights and a fan will start and then everything loses power.)

I tried all the usual tricks with no success, including clearing the static charge by holding the power button down without a battery and power source, to no avail. A week later, I discovered by accident that it would power up just fine if I removed all power sources for a couple days and then inserted the battery and the power cord before powering on. Unfortunately, if I allowed the computer to turn off for more than a restart, I would have to repeat this process. A new battery had no effect on the behavior.

It has become a fairly nice "desktop" for about four months. It has had no performance issues, etc.

I returned from a weekend trip a couple weeks ago to find the laptop off. I have tried to repeat the usual process, but either the behavior has gotten worse or my patience is deteriorating and I'm not waiting long enough. It won't power on for more than a few seconds.

Any ideas what's wrong or yet another trick to try? Any guess as to what I should try replacing? Thanks for any feedback!