might be a connection that i might have forgotten??
It's possible. However, you already stated that you "triple checked." No harm in checking again incase you blinked too fast the 3 go-arounds.
Check out KB Articles: http://support.apple.com/kb/TS1367 Troubleshooting when your computer won't turn on and http://support.apple.com/kb/TS1365 Intel-Based Apple Portables: Troubleshooting a computer that will not power on
Another option would be to take your MBP to you local Apple Store or an AASP for a FREE diagnostic test. This way you will know exactly what is wrong & how to fix since it appears you know your way around the guts of a MBP.