iMac G5 wireless internet problem

[Atlasland]

• Ok, well I had a nice happy wireless connection... until I installed the 10.4.7 update. Now I ain't got sh*t.
  
  No wireless connection. Occasionally my iMac G5 will momentarily discover my wireless network, but as soon as I try to connect, my iMac looses it again - I get the message:
  
  "There was an error connecting to Home network" (or something like that).
  
  
  
• I tried fiddling with the settings, changing channel etc, even renaming my home network, and trying to connect to that. But, no dice.
  
  About 6 months ago I had some problems with Airport, but a software update seemed to fix all that [though I'm not sure it was the update, could have been something else]. It seems that this latest update screwed it up again.
  
  And now my iMac has no internet. Brilliant. These were the kind of problems I left Windows to avoid.
  
  
  
• Any ideas? Any help would be much appreciated.
  
  Could it be being caused by interference from other wireless networks in the vacinity? - there are 2 other networks that my iMac picks up sporadically.

 

[mad jew]

If you put the router right next to the iMac, do you get the same issues?