I'm not sure exactly what happened, but if I got this right, you can logically explain why you can't be responsible for the water damage.
So, Your hard drive breaks and you go to best buy to have it fixed.
They fix it for free. (I assume it's because you have a warranty.)
A week later, it breaks and you bring your laptop back.
That's when the guy told you windows isn't properly installed and your firewall is turned off,right?
They keep for repairs or whatnot and two weeks later they call you telling there is fluid damage right ?
If that's how it happened. It's impossible that you are responsible for the fluid damage:
For the guy to think that the problem is related to the installation of windows and the firewall, he must of turn your laptop on. It must of booted windows well enough that he was able to go in the settings.
At that point it is impossible that there was fluid damage. If so, windows would not of booted. The BIOS would probably not of booted.
Since that time, the laptop is in there hands. THEY fucked up. You can explain that to them.
If it took 2 weeks before you were called and told about the fluid damage it means they sent it elsewhere. It's easy to drop a box in the snow, or carry it outside in the rain.... There could be a puddle of melted snow on the floor of the truck....
I worked at Radioshack and we hauled stuff in and out from the purolator or UPS van very quickly. If you drop something,you keep your mouth shut because it's easier that way. In winter the floor of the UPS van is quite watery and I put boxes on the floor....
....
....
yeah, ok, I wasn't a very carefull employe.
But don't worry, i don't work there anymore.