Trouble Connecting to Linksys Wireless Network

I purchased a Mac back in October and had no trouble at all with it. I was using ethernet cords to connect, and I had never bothered to try wireless. However, a little bit after Christmas I purchased a Linksys WRT300N wireless router. I hooked it all up, got a wireless network running, booted up my mac, and could not connect. I tried multiple setting with the router, and finally got it to connect without a password on the network. However, I wanted to test how stable it was, so I turned off the airport and turned it back on, trying to connect to my network again. It would not work, and I have no idea why. The only way I can get my mac to connect wirelessly is to restart all the routers setting each time I want to connect. (Note: I am currently using a PC to type this up) Any chance anyone has any hints at all?