Blackstone Group has ended its pursuit of Dell, two sources familiar with the matter told Reuters, paving the way for private equity house Silver Lake and company founder Michael Dell to buy out the world’s No. 3 PC maker. Blackstone pulled out just a month after it first launched a challenge to the billionaire’s attempt to buy and take private the PC maker he founded, while it struggles in the face of a fast-contracting personal computer market. It was not clear why Blackstone, which has been negotiating with potential partners to make a play for the PC maker, decided to pull out.