Five years ago, Nokia (NYSE:NOK) was on top of its mobile game, with 38% of the worldwide mobile phone market. Now, the company has slipped to only 8.2%. Nokia is on the mobile line of scrimmage -- and it's fourth and long. The company needs to throw a Hail Mary pass and pray their Lumia line of phones makes contact with consumers' hands. If Nokia can't get consumers to love the Lumia, it may be game over for this company.

Fumbling the snap
In the second quarter of 2007, Nokia scooped up 60% of all mobile phone profits, and by Q3 of that year the company's share of the market was larger than the next three competitors combined.

Fast forward to 2012. Apple's iPhone and Google's Android OS dominate the mobile landscape, and Samsung is the No. 1  smartphone maker. To keep from faltering completely, Nokia teamed up with Microsoft (NASDAQ:MSFT) last year and introduced its first line of Lumia phones with the Windows Phone operating system. Nokia is locked into using Microsoft exclusively as its OS, and received billions of dollars from the software company to develop and market the Lumia phones.

But despite the new OS and cash from Microsoft, worldwide sales of the Lumia dropped from 4 million units in Q2 2012 to 2.9 million in Q3 -- and Nokia posted a $1.27 billion loss for the quarter. This wasn't Microsoft's fault, though. Nokia spent the better part of last quarter talking about the new phones and Microsoft's latest OS version, which backfired. Last year's Lumia models can't upgrade to the new and improved OS, and customers took notice.

In a press conference, after the quarterly earnings report came out, Nokia's CEO Stephen Elop said, "[H]aving spent most of the quarter explaining to the U.S. population about the great innovations that are coming in Q4, one could reasonably expect that would impact sales in Q3." Indeed it did.

The investor blitz
When Nokia unveiled its latest version of the Lumia in September, it didn't announce when the phones would be available or how much they would cost. Investors responded, and Nokia's stock dropped 16% that day. Over the past five years, Nokia's stock has fallen about 90%, and with it sitting around $2.60 a share right now, the company doesn't have much more room for error.

Nokia investors need to keep an eye on sales for the new Lumia. The Wall Street Journal recently reported that Microsoft is testing versions of its own Windows phone, which would directly compete with Nokia. HTC and Samsung also have new phones on the market that run the new Windows OS, so Nokia's Lumia isn't the only phone touting Windows Phone 8.

CNET recently reviewed the Lumia 920, the high-end version, and said it's "the most powerful, feature-rich Windows phone available," but said some of the finishes on the phone make it "harder to hold and carry." If Nokia investors don't see strong sales for the new Lumia, or see competitors selling their phones in greater numbers, they may start reviewing their shares to see if they may be too hard "to hold and carry," as well.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.