Sounds like your computer reassigned your IP address that your printer was using.
In your PC “Start” menu choose “Run”
This will open up the “Run” box.
Type “cmd” and enter
This will open up a dialog box.
Type “ping” a space and then your IP address OF YOUR PRINTER (i.e. “ping 172.18.3.48”)
For more information:
http://support.microsoft.com/kb/300986
It should report back something like “pinging 172.18.3.48 with 32 bits of data” and then report back the status with “Reply from 172.18.3.48 32 bits TTL= 60” IF the connection is good.
IF the connection is BAD, OR the address is wrong it will report back something like “timed out”
If it pings, then disconnect your printer internet connection and ping it again.
If it still pings while disconnected then something else has the same IP address of your printer.