All 30 Dow stocks participated in yesterday's big rally in the wake of the European Central Bank's decision to support its weaker economies through a bond-purchasing program. Yet although the impact of a stronger Europe is unquestionably positive for U.S. stocks, that doesn't mean the stock market is going to move straight up from here. Even with troubling employment data, the Dow Jones Industrials (INDEX: ^DJI) managed to pick up 15 points today, and the S&P 500 (INDEX: ^GSPC) actually managed to do much better on a percentage basis.

Still, many stocks weren't able to hold on to all their gains from yesterday. Poor earnings forecasts were the primary factor behind two of the big losers on the day. Kraft (Nasdaq: KFT) lost more than 5% after it gave some information on what its two businesses will look like after the company's planned breakup next month. In particular, a weak forecast for the Mondelez global snack business, along with news that the Kraft grocery business will focus more on cash flow than on growth, disappointed investors.

Meanwhile, Intel (Nasdaq: INTC) had a troubling forecast of its own, as it reduced its revenue guidance well below its previous range. Everyone's been well aware that the PC business hasn't done very well lately, but even more problematic are fears that the coming release of the Windows 8 operating system may not reinvigorate the PC industry as much as Intel may have hoped. That news sent Microsoft (Nasdaq: MSFT) down 1.25% as well in sympathy, given its obvious reliance on PC sales. Both companies are doing their best to broaden their offerings into the mobile field, but both have struggled to catch up from the head-start they gave their competitors.

Keep it up
Big one-day losses can be warning signs of future problems or unique opportunities to capture good values. The real story, though, takes a much longer-term perspective to capture. Microsoft, for instance, is banking on Windows 8 for a lot more reasons than just trying to recapture its PC glory. Find out everything you need to know about the software giant in the Fool's premium report on Microsoft.