Dell keyboard and sound did not work after a coffee was dropped on my laptop

I have dell Vostro 3500 laptop and windows 7 32x. Last week i drop a coffee over my keyboard, so i turned off the laptop and i clean the key board, but the keyboard did not work well. I have attached an external keyboard and it worked well, but currently i am facing the following problems;-

1. the built-in keyboard did not work.

2. when i try to turn the sound on , i got the following message”no audio output device is installed”

3. when i turn the laptop off, the power button light will stay on, and i can not turn the laptop on unless i attach it to a charger

4. when i turn the laptop off, the key which have “9” label in the touch pad, near the blue tooth and wirelessicon will stay light on.

So can anyone advice on what might be causing this