Ethernet Shield Configuration Problem

I have a problem using arduino with ethernet shield. A few weeks ago I was able to read analog inputs and display them on the web page. But now I cannot do that. When I try to use the ready sketch "DHCP Address Printer" It gives me the error "Failed to configure Ethernet using DHCP" from the serial port screen. Again when I use the sketch " Web Server" it says "server is at ......" but when I type that address in my web browser it doesn't respond. I think there is a problem while configuring ethernet. Is there anybody who experienced a similar problem and fixed it?

Try clearing the cache in your web browser.