Networking & wireless: PLEASE help....frustrated wireless router user

PLEASE help....frustrated wireless router user

Guys, I have set up a wireless LAN router in my house wiht MAC filtering. It worked flawlessly the first day, however that nite i turned my power supply off (which the router was connected to) and the next day attempted to use my wireless connection again. This time my Laptop was not detecting the network, and i actually went back and reconfigured my router. After that, the connection was very slow and inconsistant. Looking at my cable modem, the Cable light was blinking off and on suggesting that there was a problem with the cable connection. I am hesitant to just relegate it to a cable problem as i dont have too many issues with my cable connection, and it seems to have happened after i connected the wireless router. If you guys have ANY idea as to what the problem is, please help me out....I am getting very frustrated with the wireless setup. And I am right that the router SHOULD NOT have to be reconfigured everytime its power supply is shut off.....it is a LINKSYS WRT54G....thanks guys