The second quarter of 2015 saw the sharpest decline in global PC shipments in close to two years and once again serves as a reminder that last year's brief resurgence was little more than a fluke.

According to research firm Gartner, shipments dipped 9.5 percent in the second quarter compared to the same period in 2014, down to 68.4 million units. International Data Corporation (IDC), which doesn't consider tablets to be computers, noted an 11.8 percent drop during the same period for a total of 66.1 million PCs shipped.

Despite declining sales, Lenovo held onto the top spot among PC makers with a 20.3 percent share of the market according to IDC. HP finished the quarter in second place with 18.5 percent of the market followed by Dell with a 14.55 percent share.

The PC market started showing signs of trouble in 2012 around the time when tablets exploded in popularity. The rise of large-screen smartphones only added fuel to the fire, further pushing us into the mobile-first culture we live in today.

Slowing tablet sales combined with the holiday buying season resulted in PC shipments growing by double digits late last year. Many believed this was a turning point for the industry but as we've witnessed thus far this year, the holiday spark ultimately provided a false sense of optimism.

The next several months, however, will be especially telling. Microsoft is gearing up to launch Windows 10 later this month following the lukewarm reception of Windows 8 in 2012. The early consensus is that Windows 10 is a winner and with Windows XP reaching the end of official support last year, Microsoft will no doubt have a direct impact on the PC industry in the near future.

Even still, the long-term outlook doesn't look too hot for PCs. IDC said a year ago that it expects PC sales to continue to decline through 2018.