Hi matt,
The only change you should have made to your wireless Belkin router was to update its firmware, if such an update was available for that model.
Shut down your new iMac, and also your PowerBook, until you can use your pc to get your network back to the exact working condition in which it had been, then you can put your PB back on, but wait to power on the iMac. You'll get things straightened out quickly.
If not, the likelihood is that you'll waste a lot of time and effort with little result. There won't be anything wrong at the ISP, it's all to do with adding the iMac without having the Belkin firmware updated first.
The Belkin website indicates that there is
a firmware update available for their routers. Without that, it might not be possible for your new iMac to connect properly. Once you've used your pc to get the network back with the new firmware added onto it, power on your PB, and verify that it will connect as it always has.
Once it is all back and your PB reconnects, there is only one change that should be made, if your pc can accept it - change encryption method on your Belkin from WEP to WPA Personal or WPA2 Personal. As long as your pc can accomodate it, perhaps it needs an update to do so (don't know, never used a pc), you'll be good to go:)
Once done, it will be a sure thing that your PB will again connect, except of course, you'll have to first turn on the PB's AirPort and go into its Network panel in System Preferences and select "Show: AirPort" so that you can delete (use the small - box) your network with its OLD security method from the list that will show below the selector "By default, join:" when it is set to "Preferred networks."
You'll then need to add your network with its NEW security method by clicking the + box below, and in the drop-down box, matching the Wireless Security method to whatever method your network has been changed to, then entering your network name and password, followed by clicking the "OK" button and then the "Apply Now" button. The PB should then connect, give it a few seconds, but if not it should after you turn off AirPort, then back on using the menu bar's AirPort icon, selecting your network name.
It will also be much more likely that your new iMac will be able to connect, once its needed software updates have been applied to it. I would not do the software updates wirelessly, but use an ethernet cable from your new iMac to the Belkin. Once all the updates have been completed, disconnect the ethernet cable and follow the same procedure as with the PB to delete your network from the AirPort pane of the Network panel of System Preferences, followed by adding the network back with its new wireless security method.
You may very well need to restart your iMac and your router before it'll work, but it should be ok.
Belkin's Support website is where I found the above firmware update:
http://www.belkin.com/support/
Message was edited by: myhighway