This irritated me until I figured it out. Bit of a blond moment. Oh well.
If you are running Vista, and use notepad (e.g. view source of a web page to hunt down a glitch), you may discover that CTRL+G doesn't work - and the GoTo menu option (view menu) is greyed out.
If this is the case, turn off word-wrapping (format menu), and it'll be re-enabled. Doh.