randomly won't start, dead

For the past five months now, I have been having problems with my 2000 LT 4x4 Blazer. It's fully loaded and has a Viper starter. The truck is in great condition with 32,000 miles. The problem is that it won't start. I'll jump it and then it will be fine to drive but then a couple days later it won't start again, it's dead. Nothing happens when I turn the key over, no lights in or out, just a couple of clicks maybe. I checked the battery at a Sears Auto Center and they told me the battery was fine and not to replace it. I checked the alternator and it's spitting out 14 amps which is right. So now I'm thinking it could be a short or faulty wire somewhere but I don't know how to check it. This all began after water leaked into my vehicle during a really bad rain storm we had back in the Mayish, I hate the Northeast. I'm thinking maybe some wire is corroded from rust from the water over the ceilings interior dome light possibly. Can someone please help me diagnose this problem?