Did you make any changes to your router or pc or any other equipment?
If not check the wifi settings on the printer to make sure they are set up right.
Then on the pc or laptop that you use click start then look for network. Click on network and see if the printer shows on the screen.
Click start, control panel, printers. Check to make sure the printer is online.
If you see the printer I would power the printer down and then back up and let it restart. Could be something got out of sync.
I have a HP Photosmart 7820 that goes off line due to lousy drivers from HP. If I don’t print anything for a few days the printer goes off line. I have updated all the drivers and it still happens.
If the printer still doesn't work go over to the networking forum and post there.