Hi,

Try these steps and let me know if it fixes your problem:

Step 1: Temporarily disable any security software installed on your computer and check if that makes any difference.

Disable antivirus software:  
http://windows.microsoft.com/en-US/windows7/Disable-antivirus-software

Note: Make sure you turn-on the security software and Windows Firewall later.

Step 2:Update the drivers for your printer.

Refer these links for more information:

Update a driver for hardware that isn't working properly:
http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly

Find and install printer drivers
http://windows.microsoft.com/en-US/windows7/Find-and-install-printer-drivers

Step 3: Restart the print spooler service.
You must be logged on as an administrator to perform these steps.
a. Open Administrative Tools by clicking the Start button, and then clicking Control Panel. In the search box, type administrative tools, and then click Administrative Tools.
b. Double-click Services.  If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
c. Right click the Print Spooler service, and then click Properties.
d. On the General tab, next to Startup type, make sure that Automatic is selected.
e. If the service is not already running, under Service status, click Start, and then click OK.  If you're prompted for an administrator password or confirmation,
type the password or provide confirmation.

If nothing helps, then manually add the printer to local port and check.

Step 4: Manually add printer to local port.

a. Go to control panel and click on Devices and printers.
b. Choose Add a printer and then select Add a local printer. Click on Create a new port. The default in the drop down box is Local Port. Do not change that.
 c. Click Next.
A dialogue box will appear asking for you to enter a port name. Type in the \\computer name\printer name .
d. Type your computer name and the printer name (\\PC\printer name)
e. Click on ok and exit.

Also, see:
http://windows.microsoft.com/en-us/windows7/Share-a-printer

http://windows.microsoft.com/en-US/windows7/File-and-printer-sharing-frequently-asked-questions

Regards,
Afzal Taher - Microsoft Support.
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I assume you have a network card installed for the printer.  Most likely the IP address changed after a recent power cycle.  If that is the case, either assign a static address to the printer or add new Standard TCP/IP Port using the hostname for the device rather than using a Dynamically assigned address which can change.