Hewlett-Packard Co interim chairman and activist investor Ralph Whitworth will step down on Wednesday to focus on his health, the latest top-level departure from the computer maker as it struggles to return to consistent growth. Whitworth, who will also take a leave of absence from his hedge fund Relational Investors LLC, has stood in as chairman of the worlds largest personal computer maker since Ray Lane relinquished that post in April 2013. The Wall Street Journal cited a person familiar with the matter as saying Whitworth had undergone throat cancer treatment this year. The Silicon Valley icon is trying to reduce its reliance on PCs and move toward computing equipment and networking for enterprises, part of CEO Meg Whitmans effort to return the PC maker to growth.