1990 Volkswagen Jetta

My car isnt starting. It started up fine the other day and while tryibg to fix a temperature gauge problem my brother disconnected a white plastic connection plug right above the engine and my car stopped running. We plugged it back in and after that my car wont start up again now. Not sure what that plug was but it seems to be the reason. Im sure my battery is fine amd the wires and connections are good (no corrosion).

also as a side note. My brother did squeeze a few hoses while checking my radiator fluid levels. Hoses connected to the coolantraevoir and engine. Thinking maybe this could have flooded something or somehow gotten the spark plugs wet preventing a start up?

anyways thats all I know of to tell you. Any help would be much appreciated.
February 13, 2013.

Go back and look at that plug again and make sure the pins aren't damaged and the plug is fully seated and locked together.

Feb 13, 2013.
Hi: As far as the hoses he touched, they won't hurt anything. You need to check to see if you are getting spark and fuel to the engine. One is most likely missing. Once you identify which one is missing, then you will know where to focus.