* New York City mostly spared of snow storm
* Caterpillar shares slide as low oil prices hurt profit
* Microsoft shares tumble a day after results
* Futures down: Dow 195 pts, S&P 15 pts, Nasdaq 37 pts (Updates prices, adds Caterpillar)
By Rodrigo Campos
NEW YORK, Jan 27 (Reuters) - U.S. stock index futures fell on Tuesday, weighed by company earnings results including those of sector bellwethers Microsoft and Caterpillar.
* Concerns lingered over Greece's new anti-bailout government and its implications for the euro zone. The leftist government that came to power in Athens following elections on Sunday looks set on a collision course with the country's creditors. U.S.-traded shares of the National Bank of Greece fell 16.8 percent in premarket trading.
* Shares of Microsoft fell 7.5 percent in premarket trading the day after the Dow component reported results. The main engine of its historic earnings power, selling Windows and Office to big businesses, is showing signs of waning.
* Shares of construction and mining equipment maker Caterpillar fell 6.2 percent after its net profit came in below market expectations, due primarily to the recent drop in the price of oil and lower prices for copper, coal and iron ore.
* Market participants were watching out for a snowstorm that appeared to have spared New York City but continues to pound parts of the U.S. Northeast. New York Stock Exchange and Nasdaq spokesmen said Tuesday would be business as usual.
* Economic data expected on Tuesday includes December durable goods orders at 8:30 a.m. EST (1330 GMT), November Case Shiller home prices half an hour later and Markit's gauge of the U.S. services sector growth at 9:45 a.m. (1445 GMT). New home sales and consumer confidence data are also due shortly after the opening bell on Wall Street.
* Facebook shares fell 1.1 percent premarket after access to the world's largest social network and its Instagram photo-sharing site was blocked around the world for up to an hour on Tuesday. The company said the reason was an internal fault and not an outside attack.
* Procter & Gamble shares fell 2.5 percent in premarket trading after the world's largest household products maker reported a near 31 percent fall in quarterly profit, hurt by a stronger dollar.
* Pfizer reported stronger-than-expected quarterly results as sales of vaccines and cancer drugs increased, but the company forecast 2015 earnings below Wall Street expectations and its shares fell 1.1 percent in trading before the opening bell.
Futures snapshot at 7:56:
* S&P 500 e-minis were down 15 points, or 0.73 percent, with 123,497 contracts changing hands.
* Nasdaq 100 e-minis were down 37 points, or 0.87 percent, in volume of 22,748 contracts.
* Dow e-minis were down 195 points, or 1.11 percent, with 21,695 contracts changing hands. (Reporting by Rodrigo Campos; Editing by Chizu Nomiyama)