Pressing power button has no effect

[kmcbarne]

I was upgrading the RAM on my out-of-warranty laptop, and had to troubleshoot it not detecting the additional RAM.  I removed the new RAM, and placed the original RAM chip into bank 2 (to verify that the bank itself wasn't bad).  The laptop booted up, and the RAM was detected, so I powered down the laptop in order to make additional changes to the RAM configuration.  I then placed one of the new RAM chips into bank 1, leaving the original chip in bank 2, and tried to power on again.  This time, however, when I pressed the power button, nothing happened, and the laptop has not powered on since.

I've checked every cable and everything is connected.  The first time this happened, I did notice that the WLAN chip wires had disconnected, but I reconnected those without an issue, and still cannot get anything to happen.  None of the internal components touched anything electrical or metal, so I don't think anything could have shorted out.  The charging LED lights up whenever I plug in the charging cord, and the battery is fully charged, it just won't power on.

[kmcbarne]

Are there any diagnostic steps for when a computer won't boot at all?  How do you check that the power switch and cable are working?

Please someone help with this, the laptop is just sitting there dead.