Today's gains set the mood for the rest of the week, and Wall Street would certainly welcome a different mood from the one we saw last week, which registered as the worst of the young year. Although the Dow Jones Industrial Average's (^DJI -0.98%) gain of 19 points, or 0.1%, may seem meager, 60% of the index's components were up. The Dow closed at 14,567. 

Investors decided to keep buying Microsoft (MSFT -2.45%) stock, even after it jumped 3.4% on Friday. The recent bullish sentiment -- shares surged 3.6% today -- comes after an earnings report that far exceeded expectations. Last week's results showed shareholders that the new Windows 8 operating system isn't a complete failure, though it did have some trouble catching on. Microsoft's stock has risen 7.1% in just the past two days on the heels of its surprising quarter.

Speaking of surprising quarters, Caterpillar (CAT -7.02%) shares tacked on 2.8% -- its largest single-day gain in three months – after the company shared optimism for the state of construction equipment demand in China, one of Caterpillar's most important markets. That said, first-quarter profit was down dramatically from a year ago: It earned just $1.31 per share, compared with $2.37 per share a year ago. The company also forecast sales this year to be in the range of $57 billion to $61 billion, down significantly from the $60 billion to $68 billion range it had expected before. 

Unlike the prior two companies, DuPont (DD) didn't report earnings recently. But like the prior two companies, its stock was up big time today, adding 2.5% as the markets eagerly awaited its earnings report tomorrow morning. Analysts expect the diversified chemicals company to earn a little less than 1% more than it did a year ago, though sales are expected to be down more than 7%. 

Lastly, shares of General Electric (GE 1.30%) ended the day as the worst-performing in the Dow, losing 1.8%. Like Microsoft, GE stock is simply continuing the momentum it had going into the weekend after reporting earnings. Unlike Microsoft, that momentum is negative, and today's downgrade by JPMorgan Chase from "overweight" to "neutral" reflects Wall Street's reservations about the health of the business.