Stock prices advanced broadly this morning in early, moderate trading after the Tokyo market and other overseas exchanges regained strength. The Dow Jones average of 30 industrials gained 7.66 points to 2,591.22 in the first half hour of trading. Advancing issues outnumbered losers by more than 2 to 1 in nationwide trading of New York Stock Exchange-listed issues, with 620 up, 286 down and 467 unchanged. Volume on the Big Board came to 21.87 million shares as of 10 a.m. on Wall Street. On the Tokyo Stock Exchange, the key Nikkei index rose more than 400 points in early trading, but then plunged on a wave of computer-guided selling by foreign institutions. But the Japanese market recovered as investors gradually returned and computerized buy programs kicked in. By the close, the Nikkei index gained 92.51 points, or 0.25 percent, to move to 35,826.84. On Wednesday, the Nikkei plummeted more than 3 percent for its third-worst drop ever. The plunge helped set off a tumble on Wall Street, but the U.S. markets later recovered as institutional investors took advantage of bargains. This morning, the NYSE's composite index of all its listed common stocks gained 0.30 to 181.37. At the American Stock Exchange, the market value index was up 0.63 at 353.58. On Wednesday, the Dow Jones average of 30 industrials closed down 13.29 points to 2,583.56. Declining issues outnumbered advances by about 5 to 3 in nationwide trading of New York Stock Exchange-listed stocks, with 577 up, 963 down and 455 unchanged. Volume on the floor of the Big Board totaled 159.24 million shares, up from 147.30 million in the previous session.