I have several computers at home but only my iMac is having wi-fi problems - around once a day wi-fi stops responding. When I turn my wireless off and immediately back on, it works again. Is this a hardware problem? Software problem?

I'm running a newish iMac running Lion and an Airport Express on Comcast.

Thanks!

I have several computers at home but only my iMac is having wi-fi problems - around once a day wi-fi stops responding. When I turn my wireless off and immediately back on, it works again. Is this a hardware problem? Software problem?

I'm running a newish iMac running Lion and an Airport Express on Comcast.

EDIT: I should mention that nothing has changed in my setup aside from some software updates. Basically, I am trying to determine if this is a hardware or software problem and was hoping to find out what steps I can take to investigate.

Thanks!