Printer driving me crazy

[Aldarion]

After I reinstalled Windows 7 and changed a few modems (I was dithering between cable and ADSL internet providers) my WiFi-capable Canon Pixma MX455 stopped printing.
Whenever I send something to print, I get answered by "printer not responding" from Canon's printer status dialog.
I tried reconnecting it: went to Wireless LAN setup, found my access point, put in the correct WAP2 key and got a "Connected. Press OK" message. All nice and good.
But still - nothing got printed. So I tried reinstalling it from the disk that came with it. Nothing. The detection fails.
At one point the installation wizard ordered me to connect the printer to the computer with a USB cable. I did so, but the printer detection wizard still couldn't find it on the home network. Said it couldn't find the printer's IP address. So I found the "print LAN data" in the printer's setup menu and fed Windows the exact address on the print-out. Nothing.
Frankly, I'm completely flabbergasted; the printer seems to be completely fine (e.g. the copying functions perfectly), and it claims to be wholly connected to my WiFi, but Windows cannot detect it, neither from Add Printer nor Add Device.
What can be done?

Edit: Tried installing it with the USB cable option (screw the WiFi, I just want to print!)
Nothing. The installer said the printer had been detected, but whenever I try to print - "Printer not responding".

[Sizik]

Have you tried manually downloading and installing the drivers from the manufacturer's website?

[Aldarion]

Yes. The driver installs fine (and when I plug the printer in via USB it auto-detects it and installs drivers. But whenever I actually try to print, or view printer status, it's as if the thing's completely turned off.

[nantzjoy]

There might be various reasons behind it, I suggest you to check network discovery status, it should be turned on.
Control Panel>>Network and Internet>>Network and Sharing Center>>Turn on network discovery and Apply. Check again if you can print now.

[Tyndmyr]

I had the same issue with my Canon for USB, but in wireless, it worked just fine. Note that I had to power cycle etc, as per the instructions, a coupla of times to get it to "worked just fine".

Apparently, the driver installation is very finicky about the "when you turn it on" aspect of getting set up. Works like a charm after the setup, though.

[Neil_Boekend]

According to my experience with home grade printers this seems to be behavior as designed. Dang things always drive me crazy.