HP Pavillion starts up and shuts down but not all the time

Hello MajorGeeks,

I am really hoping to get some insight here as I have done everything I know how to do on this one. Let me say from jump that I don't have a whole lot of experience doing laptop repairs...mainly pc's.

My client has an HP Pavillion Entertainment Center (dv7) which needed a keyboard replaced after spilling liquid on it. As I was waiting for parts, I loaded Office 2007, installed security, etc. using an external keyboard and the machine was working fine.

To do the replacement, I had to basically disassemble everything to remove the old keyboard and insert the new one. I then reassembled it putting back the memory modules, hard drive, wi-fi cards, dvd player, etc. She booted up fine. As I was testing the components, I got online and Windows updates started installing. After about 4-5 minutes, the screen flickered and went black.

There is no consistency to what the machine is now doing:
1. Sometimes when I power it on, I can get to the desktop and within 3-4 minutes the screen flickers and I get a black screen.
2. I power it on and can hear the fan and hard drive as well as see the LED lights but get a black screen (no cursor, nothing)
3. I power it on and it shuts off in seconds.

Thinking there was a short somewhere, last night I completely disassembled and reassembled the machine to no avail. I am still getting the 3 inconsistencies above.

Does anyone have a suggestion?