My iMac g5 won't connect to a wireless network

Hi, this has worked for a few...

Though all of these steps may or may not be needed, I'm including them all.

Make a New Location, Using network locations in Mac OS X ...

http://support.apple.com/kb/HT2712

10.7 & 10.8…

System Preferences>Network, top of window>Locations>Edit Locations, little plus icon, give it a name.

10.5.x/10.6.x/10.7.x instructions...

System Preferences>Network, click on the little gear at the bottom next to the + & - icons, (unlock lock first if locked), choose Set Service Order.

The interface that connects to the Internet should be dragged to the top of the list.

10.4 instructions...

Is that Interface dragged to the top of Network>Show:>Network Port Configurations.

If using Wifi/Airport...

Instead of joining your Network from the list, click the WiFi icon at the top, and click join other network. Fill in everything as needed.

For 10.5/10.6/10.7/10.8, System Preferences>Network, unlock the lock if need be, highlight the Interface you use to connect to Internet, click on the advanced button, click on the DNS tab, click on the little plus icon, then add these numbers...

208.67.222.222

208.67.220.220

(There may be better or faster DNS numbers in your area, but these should be a good test).

Click OK.

Additionally:

it would also help if you put some specific info regarding your iMac model in your profile; you are certainly not running Lion on a G5 since Apple discontinued those in 2006.

You said you have a Core Duo? Is that correct?

If so, you son't be able to run Lion:

http://support.apple.com/kb/HT4949

(requires a Core 2 Duo)

Have you tried connecting it via wire directly to your modem (not wirelessly)?

This is not my area of expertise, so did you try all of BDAqua's suggestions?

Ahh, Best Buy - I'd take it in. Actually, I personally would not trust Best Buy with my Mac, but since that is where you had it done, you will have to deal with them.