No yeast for a week. Is it ruined?

I'm not really a nub, but I"ve never had this happen. I had made a starter for my Maibock a couple of weeks earlier, and let it sit in the fridge until I got ready to brew. It was a big starter, but it grew just fine and was only a couple of weeks old.

But I brewed last week and pitched the starter, and there was just no activity whatsoever for a full week. At first I thought it was just slow to start, then I thought it was extra slow because it was at 50 degrees. By the time I figured out it wasn't going to take off, I couldn't get more yeast for a couple of days.

But the wort stayed at 50 degrees the whole time, and was hopefully sanitary. I rack straight from a closed kettle into an almost closed and sanitized conical, so not much contact with the outside world.

What are the chances it's ok? Have people let wort sit, semi-chilled for a week and everything ends up fine?

For whatever reason, the last few ales I've made have had absolutely no "signs" of fermentation in the traditional sense. No real bubbling in the airlock, only a slight krausen, etc. but all have finished out in the appropriate range. Are you able to take a refractometer reading (or if you've got more wort to spare and a sanitary racking process, a hydrometer reading)?

It should be fine. Only way to know for sure is take a reading. Can you see any krausen at all? I'd be shocked if properly sanitized yeast wouldn't ferment beer just from a little nap at 50 deg.

Most lager ferments aren't that exciting anyway. No beer fountains from stuck blow-off tubes, etc. like you can get with ales.
So how do you tell what's going on? By taking samples.
A LOT of people underestimate the amount of yeast required to do a proper lager pitch as well. If you pitched small, the yeast may well be busy reproducing. Again, measuring will tell you what's going on.

Thanks for the replies, but no, there was no fermentation. Not just no bubbles - the wort was totally sweet. Didn't even need to do a reading, it tasted just like it was out of the kettle.

I bought new yeast on Saturday and pitched it Saturday night, and now it's fermenting just fine. So I have no idea why the original yeast died, but I guess they did.
And I've underpitched now, since I couildn't afford $20 or more for yeast and couldn't make a starter.