Internet Down - Help!

[onlineapps]

Somehow, my ethernet broadband is down. I've got a dual-boot setup, and for a while Kubuntu was running fine. But now, it's internet is down. I had installed the following (not sure if this is why):

iTunes, QuickTime alternative, and quicktime through WINE
SAMBA
Maybe some more that I forgot?

Anyway, any help would be appreciated.