NEW YORK (CNN/Money) - Computer security provider Network Associates said Friday it would restate its financial results for 1998 through 2000.

Executives of Network Associates, who previously have said the Securities and Exchange Commission was focusing on its 2000 results, said in a conference call Friday that the agency also was likely to include 1998 and 1999 in its investigation.

They also said the accounting errors that led to the restatement could be traced to a single employee.

Network Associates (NET: up $1.33 to $21.62, Research, Estimates) shares rose more than 6 percent in New York Stock Exchange trade Friday. J.P. Morgan analyst Sterling Auty changed his rating on the company's shares to "long-term buy" from "market perform" Friday and attributed the rise in the stock price to confidence in the company's new management team.

"The fact that the issues that caused the restatement happened at a time when (the company) was run by old management is a positive for the credibility of the new management," J.P. Auty said. He also noted the restatements were small and were non-cash related.

"The stock is up because the (internal) investigation was a negative cloud over the company and now that's gone," Auty said. He said he raised his rating on the stock to "long-term buy" rather than to a "buy" because the SEC probe is still under way.

Network Associates said the restatement will increase its 2000 net loss by 16 cents per share, cut its net loss for 1999 by 2 cents per share and cut 1998's net gain by 3 cents per share.

The Santa Clara-based company said its results from operations for 2001 and 2002 will remain unchanged, but that it would restate its balance sheet from last year's fourth quarter and this year's first quarter.

Network Associates Chairman and Chief Executive George Samenuk told analysts during Friday's conference call, "We believe that we have a clear and complete understanding of the scope and magnitude of the inaccuracies and can accurately restate our financials for the affected periods."

The company said its results for 2001 and the 2002 first quarter would not be affected by the restatements. Executives also said the restatements were already incorporated in its financial guidance for 2002.

The company said it expects to file restated financial statements with the SEC by the end of June.

Samenuk said the accounting problems were discovered during a routine tax filing, and they appeared to have been caused by a single employee, who he did not name.

"All of the inaccurate transactions appear to be linked to one individual, so we reviewed every transaction related to that individual regardless of size. We also reviewed transactions related to individuals in the company closely associated with the person in question," Samenuk said.  

--From staff and wire reports