Haunted by weak PC sales and an Apple (NASDAQ:AAPL)-Samsung alliance for memory chips, Micron (NASDAQ:MU) stock sagged Friday, continuing a general downtrend that began in December. Still, Summit Research analyst Srini Sundararajan upgraded Micron stock Friday on the premise "that 12-18 months from now, MU will likely be trading at least 20% higher from where it is today." Micron stock hit a wall when Samsung announced a deal with Apple to produce about half of the DRAM chips the Cupertino, Calif., company needs for its iPhones. Samsung competes with Micron in memory chips. View Enlarged Image That slump was followed by lower-than-expected guidance by Micron for its fiscal Q4... More