Microsoft ( MSFT) launched a new, free anti-spyware product Thursday and announced plans to release a virus removal product next week, spurring more speculation about when the software behemoth will jump full force into the security market. Based on technology acquired last month from Giant Company Software, the first beta of the anti-spyware software detects and removes spyware and improves Internet browsing safety, according to Microsoft. In addition, Redmond, Wash.-based Microsoft said a new, free tool to remove malicious software -- developed from technology acquired from a Romanian firm in 2003 -- will be available Jan. 11. The tool removes viruses or worms that already have infected a computer and will be updated the second Tuesday of each month. Microsoft, whose Windows software is a huge target of virus and worm attacks, said the virus removal tool is designed to augment anti-virus solutions from other companies such as Symantec ( SYMC) and McAfee ( MFE) that provide more complete coverage. Microsoft's removal tool doesn't protect against a new virus attacking a system. But Microsoft is widely expected to launch and charge for a broader competing anti-virus product this year -- a threat that has added to pressure on Symantec stock since the company announced its merger with Veritas ( VRTS) last month. Shares of Symantec, which was downgraded by one analyst and upgraded by another Thursday, recently dropped $1.54, or 6.2%, to $23.50. Rival McAfee also suffered a hit, shedding $1.16, or 4.4%, to $25.47 in recent trading. Shares of Microsoft were up a penny at $26.79. Wedbush Morgan Securities analyst Kevin Trosian wrote Thursday that Microsoft may launch a competing anti-virus product as early as February or March -- months earlier than other predictions. However, Trosian said he doesn't expect Microsoft to affect the consumer anti-virus market for the next 12 months or the enterprise anti-virus market for at least 18 to 24 months.