[morticaixavier]

If you get zero activity after a few days then all the yeast were dead. The problem is that if you pitch a large amount of yeast (such as a whole vial of yeast) in to a small amount of wort (such as a starter) then the fermentation can occur quickly and without much visible evidence so you only think nothing has happened. I often make starters at night and wake up to what initially looks like an unaffected starter but actually fermentation is just done. After you have made a few starters you will be able to look at it and tell whether it has fermented just by the color and clarity. You can also swirl or shake the starter and see CO2 coming out of solution. That is usually how I tell whether I am looking at the starter before or after fermentation has started.

Unless the beer kit sat under a Christmas tree that was on fire it is almost certain that you have plenty of live yeast in that vial. Our beers sit at room-ish temperature for 2-3 weeks and you can repitch the yeast from one batch into the next. Yeast naturally live at ambient temperatures. I expect your starter fermented out quickly and you have a big pile of healthy yeast ready to tackle some beer.

this is a good point and could well be the case. you can take a gravity reading of your sample and determine if any fermentation has occurred

[fm8756]

Looks like I'm starting to get some bubbling in the air lock!  I'll take that as a good sign!

How exactly do you "decanter"?

[a10t2]

Looks like I'm starting to get some bubbling in the air lock!  I'll take that as a good sign!

Yeast need oxygen to reproduce, so get rid of the airlock and cover it with some foil instead.

How exactly do you "decanter"?

Once it's fermented out, put the starter in the fridge for a day or two, then pour (decant) off as much liquid as you can, leaving the yeast solids behind.

[fm8756]

So the yeast starter went well!  But I used 2 cups of DME that was meant for the recipe. Do I need to get more DME for brew day or just not add as much?

[Frankenbrew]

Either/or. It depends on whether or not you want to hit your target gravity perfectly thereby ending up with the projected ABV%. Usually a little bit more or less extract won't matter that much. All grain brewers routinely are up or down a few gravity points on every batch, so depending on the recipe and your goals it shouldn't change the finished product much.

[wingnut]

Either/or.

+1
The couple cups wont make a noticeable difference in the finished product. 

I always look forward to reasons to stop by the local homebrew store, but this certainly not a reason to put off brewing a batch of beer!   Let it rip!