Problem with AirPort! Really bizarre!

Hello,

2 nights ago I shut down my iMac before bed and it was operating perfectly that night. The next day I get home from work and try to go onto the Internet and it said I wasn't connected. I initially suspected my router down stairs to be unplugged - but no - it was fine. My airport seems to be really screwy as it never connects to my home's wifi! It used to work fine before! I try to fiddle around in my airport settings but it is very unresponsive and does not connect to any networks, it won't even bring up the neighbour's wifi! It just sits there scanning for networks for infinite time! I also had three fatal error messages come up telling me I needed to power down by holding the power button on occasion when I try to shut down my mac... What's going on? Any ideas? My system works fine, it's just safari and airport in general!

Thanks,
Stephen