Can't Connect to Anything

I've a computer here, its a fairly new packard bell, all factory settings. When I try to connect to the internet, it dials up and seems to be working, but webpages dont display and e-mail doesn't work and my telnet client won't work. I've tried both IE and Mozilla Firefox, with firewall on and off. Nothing seems to work, but pinging from the command prompt does work.
I've also tried connecting it to my network to use the DSL modem, but this hasn't worked either and it can't go online or even access my other PCs. Any ideas?

 

The O/S in use would be a big help.

For XP, try the following two fixes:
WINSOCK Fix XP: http://www.spychecker.com/program/winsockxpfix.html
Reset TCP/IP Stack: http://support.microsoft.com/default.aspx?scid=kb;en-us;299357&Product=winxp

For other versions of Windows, try this: WINSOCK Fix WinALL: http://www.cexx.org/lspfix.htm