Windows Vista Won't Go Online Unless Connected To Router

My Windows Vista won't go online unless it is connected to the router now like it used to, and I have no idea why, it didn't used to be like this, I don't remember when it started doing this but it was when I still lived with my parents, and the last time that I had to move both of my computers out of my room do to a leak on my desk that had to be fixed it was sometime after that that it happened because after that I could only keep it on the table or if I removed it from the cord it wouldn't go online. I just know it's been a long time since it last went online on it's wifi with out being hooked up to the router. I do know that in November 2010 that Thanksgiving this computer did get wet with the leak in my room from the roof that was built on part of the house that wasn't done properly the day I nearly lost everything in my room, when I saved my computer by noticing what was going on, and moving it to the table next to my other computer so it only got some water on it that day. But Daddy doesn't even know why it's wifi quit working. Why did my wifi on my Windows Vista quit working, and I have to have it connected via router now?