TouchStone Software Corp., citing lower sales of its antivirus product and eroding prices, said Friday it expects to report a second-quarter loss on lower-than-expected revenues. The Huntington Beach maker of personal computer software also said there has been a general slowdown in the market, which is awaiting the release of Windows 98. TouchStone did not provide specific estimates of its losses or revenue for the quarter ending June 30. For the second quarter last year, the company posted a loss of $1.2 million, or 15 cents a share, on sales of $1.9 million. The results were disclosed after the stock market closed Friday. The company's stock was up 6 cents a share to $3.