In this tough market environment, many stocks have seen their value fall by -30% or even -40%. But I came across a foursome of stocks that have fallen a whopping -70% since the end of February. But don’t blame the bad economy: these stocks are stumbling for company-specific reasons. For those in search of value, it’s fair to wonder if the selling has been overdone. With expectations now very low, these stocks could see fresh interest if their problems prove to be short-lived.

Medivation (Nasdaq: MDVN)
This company was a rising star in 2009 on the heels of a promising drug that appeared to effectively treat prostate cancer. Investors anticipated a lucrative marketing deal would be announced, and sure enough Japan’s Astellas eventually signed on with the promise of up to $700 million in funding if the drug worked as promised. Shares doubled from early March to late October, rising to $28.

On the heels of that Astellas deal in October, some analysts came out with bullish predictions that shares would eventually rise to $50 or even $60. Analysts at Emerging Growth Equities thought Medivation would be on track to earn more than $6 a share by 2013.

Six months later, in early March, investors learned that such potential rewards come with risk for biotech stocks. Phase III clinical data proved disappointing, sending shares down -70% in just one day. The shares have hovered around $10 ever since. The stock price is supported by around $7 a share in cash, and some analysts note that Medivation has a few more clinical trials underway that are still showing promise in the treatment of Huntington’s Disease and Alzheimer’s Disease. But analysts at Brean Murray predict that Medivation will stumble in these trials as well, and shares will eventually fall to $6. Net it all out, and there’s little reason for optimism for a near-term rebound. But if shares continue to drift lower and the company releases further positive data from current clinical trials, shares could find new life. Put this one on your watch list.

Corinthian Colleges (Nasdaq: COCO)
I recently took a look as the for-profit education space and my conclusion still stands. Corinthian Colleges has a pretty dismal record in terms of student loan re-payments, which means that the U.S. government is inching closer to cutting off funds from which students can borrow. If and when Uncle Sam formalizes that plan, shares could fall even more. Steer clear of this troubled stock.

[Read: A New Federal Report Reveals Which of These Stocks to Buy]

Dex One (Nasdaq: DEXO)
Never heard of Dex One? Neither had I, until I dug deeper and saw this is the former yellow pages publisher known as R.H. Donnelly, which skidded into bankruptcy in June, 2009, thanks to a crippling debt load. The company worked out a deal with creditors and shed half its debt and went public again in February under a new name. Bad move. Debt was reduced, but not nearly enough — Dex One is still sitting on $3 billion in debt and has just $100 million in cash in the bank.

The company has two other strikes against it. First, sales are declining, most notably in its core yellow pages business, as consumers increasingly use search engines to find local businesses. Second, the company is having an awfully hard time finding a suitable candidate to run the company. Right now, board members are doing their best to keep the ship afloat.

If sales eventually stabilize and a new competent executive can be found, this stock could eventually find new support. The stock has fallen so low that it trades for just three times free cash flow. But investors have no assurance that cash flow can be sustained. If sales and cash flow fall, then Dex One’s large debt load would send it right back into bankruptcy. Keep an eye on this one, but don’t let that free cash flow multiple tempt you just yet.

Broadwind Energy (Nasdaq: BWEN)
When JP Morgan initiated coverage of this wind energy equipment supplier with a “Buy” rating on March 9th, shares rose more than +6% to $5.44. At the time, JP Morgan’s Chris Blansett predicted that “wind industry fundamentals are near a bottom,” adding that “the wind industry will grow +25% over the next three years … and Broadwind will outgrow the wind industry.”

That would be the last time shares ever touched such heights. Just three days later, management announced weak fourth quarter results, pushing shares down more than a buck. JP Morgan acknowledged that their bullish outlook was perhaps premature, but then noted that “management thinks this is as bad as it gets.”

Not by a long shot.

The bad news kept coming, ultimately forcing JP Morgan to slash its 2010 revenue forecast from $217 million to around $150 million. Any remaining hopeful investors finally ditched the stock, and it finally slipped below $2 last week. Paradoxically, this is precisely the time to find value in a stock like this.

For starters, management has finally learned to sharply lower guidance, rather than see forecasts suffer from death by a thousand cuts. Thanks to recent contract wins, that new lower sales forecast actually looks achievable. In addition, Broadwind isn’t losing business to rivals: the entire wind industry is expected to post a revenue drop even greater than the company’s -25% dip. The real culprit is a wind market that has been slow to develop due in large part to stalled climate legislation in Congress.

But many believe that we will eventually see a comprehensive energy package signed by the White House that boosts subsidies and tax credits for this clean energy. The good news is that Broadwind Energy is moving closer to break-even, and even though cash is dropping, it appears sufficient to fund operations for the next year, which should help avoid potentially massive dilution that any share offering would bring.

This is clearly a high-risk situation as there is no guarantee that the wind industry will ever reach the size that many expect. But after a -70% drop and a set of future expectations that can more easily be achieved, this stock is starting to hold a great deal of appeal. After steadily falling, shares appear to have found a floor around the $1.60 range in recent sessions. I like to see a bit of a rebound before jumping into a stock like this, as it signals that the sellers have been flushed out. If shares can move back up above $1.70, they may be worth a small speculative position.

Action to Take –> Of these stocks profiled here, Dex One is an impressive cash flow machine, but the risks may be too great. Shares of Corinthian Colleges hold little appeal, and Medivation might look more appealing down the road. Only Broadwind Energy holds clear appeal at current levels — albeit with some risk.