I had this problem with an SX425 recently. First of all remove all the Epson Software from the laptop and reboot. Then use the Epson CD to reinstall it but don't use the secondary device option. Treat it as a brand new wi-fi installation and install everything using the express method. (Not Custom install)
If that doesn't cure the problem. Make sure the printer is shared on the desktop computer and set up the wireless manually on the printer settings menu.