What temp did you pitch at?
What kind of yeast are you using? dried? smack pack?
What is the temp of the wort now?
Unfortunately some of the packaged beer kits come with old yeast that's no longer viable so that could be the case. In which case what you'd want to do is buy a smack pack or some more dired yeast and simply repitch.
Don't worry. Unless you used unsound sanitation you should be OK.
I'd give it a week open the bucket after a week ( not anonther 7 days but a week since you intially pitched ) if there are no signs of krausen on the sides of the bucket, I'd repitch.
I have to disagree with BierMuncher on a hydrometer being the only way to test it. In addition to looking inside the bucket, you can taste it. If you don't see any sign of Krausen it will taste sweet.