Dell, H-P fall on weak PC sales; Facebook up By: MarketWatch January 11, 2013 at 11:27 AM EST Sales of PCs slumped more than 6% in the fourth quarter, according to IDC. Facebook gets a boost from J.P. Morgan, denies report of Instagram drop. Read More >> Related Stocks: Facebook Hewlett-Packard Microsoft PHLX Semiconductor Sector Index Splunk Inc