Tokyo stocks opened lower Monday on selling of technology issues after their U.S. counterparts fell amid a massive global system failure late last week. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 253.57 points, or 0.63 percent, from Friday to 39,810.22. The broader Topix index was down 13.10 points, or 0.46 percent, at 2,847.73. On the top-tier Prime Market, decliners were led by precision instrument, mining and rubber product issues. At 9 a.m., the U.S. dollar fetched 157.40-43 yen compared with 157.45-55 yen in New York and 157.31-33 yen in Tokyo at 5 p.m. Fr…