Security light on?

Bought this car a couple of weeks ago from a used car lot. It ran just fine except for needing to get the struts or shocks looked at. Last Saturday night I went out. When I was leaving to go home I nicked a metal pole on the drivers side and it ripped the bumper cover off. Both headlights were loose as well. While getting them back on enough to get home I noticed that the bolts that are supposed to hold the lights in place were rusted or bent. There were no nuts on them or anywhere around. And only one pin still holding the cover on. There was one that was still in place but broken. There were no pins on the ground. So I don't think that the lights or cover were attached how they should be when I bought the car. I drove it to a 7-11, and then home. The next day when my fiance tried to go to work the car would either try to turn over but not, or turn over and then turn itself off. We saw that there was a blinking red light on the dash. I looked it up and found out it was a security light and it was probably Pickering the car from starting. So, I put the lights and bumper cover more securely on the car, how they were when I bought the car it would seem. Then the car wouldn't turn over at all. I have tried everything that I have found to try to reset the system/computer/codes and nothing has worked. I have unhooked the battery, taken out the right fuses, checked all of the fuses for blown fuses, unhooked the PCM, turned the key to the on position and left it for a bit, held the key in the unlock position in the door for a bit, turned the key back and forth in the door, and used a code reader to see whats wrong and erase the codes. The code reader said no codes found. The hood of the car does not stay latch down completely, but it's been like that since I bought it. And I have now found water on the passenger floor, front and back, more in the back. What could be wrong and how do I fix it?