New iMac must cycle WiFi

Please post the output of Etrecheck, and post the report here — we can have a look at the hardware and software configuration from that. If you want to see what the report looks like and how the tool is used around the forums, run a few searches for that term, and you should find many examples posted.

Why do I ask about the hardware and software? OS X 10.7.3 is rather old and AFAIK won't boot on a current-generation (new) iMac.

Etrecheck can sometimes spot problem software — some of the anti-virus, anti-malware, performance-enhancement, cache-cleaning, disk-saving widgets have been known to cause problems. Sometimes there's adware or malware installed, too.

Did you download and install this OS X software, or did you acquire it already installed and ready to be configured for you on first use? (Or did you get a preinstalled and pre-configured environment and a login password, as sometimes happens?)

I'd confirm that the Wi-Fi is working and you're not getting interference from other Wi-Fi networks in the area — move to 5 GHz, if at all possible — and then — if this is a new iMac — contact Apple Support. If this is a new-to-you iMac that you didn't install OS X on and didn't configure, then I'd likely back up all of my own files to external storage, download the most recent version of OS X supported by this iMac from the App Store and build an installer, then wipe the disk and reinstall that most recent version supported by the particular iMac, and see if that works any better.

The Etrecheck report might spot some configuration or software issues.

But if it's brand new, ring up Apple Support and ask for help — particularly if you're still in the warranty period.