macbook wont turn on

First it is not a virus. You can try resetting the SMC and since you're getting a startup chime the pram. You don't say which model MacBook you have so look at the SMC instructions and choose the right procedure, pram is the same for all. If these don't work you will probably need to take it in for service.

To reset the SMC

MacBook and MacBook Pro

Laptops with a battery you can remove

Shut down the computer.

Disconnect the MagSafe power adapter from the computer, if it's connected.

Remove the battery.

Press and hold the power button for 5 seconds.

Release the power button.

Reconnect the battery and MagSafe power adapter.

Press the power button to turn on the computer.

Newer Mac portables with a battery you don't remove

Shut down the computer.

Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.

On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.

Release all the keys and the power button at the same time.

Press the power button to turn on the computer.

Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.

Resetting NVRAM / PRAM

Shut down your Mac.

Locate the following keys on the keyboard: Command (⌘), Option, P, and R. You will need to hold these keys down simultaneously in step 4.

Turn on the computer.

Press and hold the Command-Option-P-R keys before the gray screen appears.

Hold the keys down until the computer restarts and you hear the startup sound for the second time.

Release the keys.

This definitely isn't a virus.

What it sounds like, to me, is a hardware issue. Mike's solution for resetting the SMC isn't a bad thing to try, but I don't have high hopes that that will help. Especially given the fact that your screen "flipped out" for about a minute... that sounds more like a hardware issue. Water and electronics don't mix, and 200m is a long way to walk in the rain. It's entirely possible that your machine has water damage. You'll want to get it looked at by Apple, but note that any water damage will be solely your responsibility, and not covered by warranty. (I would avoid mentioning the rain, so as not to prejudice them towards a specific diagnosis... but there are moisture sensors inside, so if that is the cause, they'll know.)

Nope, it's got to get looked at, I'm afraid. If it just plain won't turn on and you've tried an SMC reset, you're definitely looking at a hardware issue.

Agreed. My MacBook recently had a similar issue without the water, it didn't end well.

As I pointed out, it's definitely not going to be covered by warranty if it's water damage (which seems likely). If it's not, that will depend on whether your machine is still under warranty and what the problem is. There's no way to estimate the cost, as it's impossible to say exactly what components might be affected.

You should definitely make an appointment if you're going to an Apple Store. Walk-ins typically leave frustrated. Most Apple Stores are simply too busy to accomodate walk-ins at the Genius Bar. Make an appointment here:

http://www.apple.com/retail/geniusbar/