Investors are buying up stocks again, sending the Dow Jones industrials above the 8,000 mark for the first time in nearly two months. All the major indexes soared about 4 percent on Thursday as optimism grew following more signs that the economy is on the mend. Financial stocks led the rally, getting a big boost after the Financial Accounting Standards Board relaxed accounting rules forcing banks to value their assets at current prices. The change should help banks reduce losses. Another positive indicator on the economy also lifted Wall Street sentiment. Factory orders posted a large increase in February, coming on the heels of better-than-expected readings on pending home sales, manufacturing activity and auto sales the day before.