No longer able to connect to Windows computer

I have two Windows computers on my network, an XP and a Win7. Until recently I was able to connect to both computers. Using the finder:
Go|Connect to Server|smb://OFFICEINSPIRON
Suddenly I am no longer to connect to either computer. The shares have not changed on the Windows computers. I can successfully ping the computers.

Any thoughts as to what might have happened?

Thanks
Monty

Sounds like DNS is down.

Try using the IP address rather than the name

I rebooted the Windows computer and I could connect to the computer
Monty