Microsoft said Monday it has set up a secondary Web site for users affected by an Internet virus that will seek to block them from the software giant's regular Web sites.

The virus, called "Mydoom.B," was programmed to launch an attack on Microsoft's site on Tuesday, two days after a variant shut down the site of The SCO Group, a small Utah software company. The virus sends hundreds of thousands of requests for the site per minute, crippling it.

Stephen Toulouse, security program manager at Microsoft, said users who can't access Microsoft's main Web site can go to this new site. That alternative site will offer security tips as well as regular information about Microsoft products.

The virus is a variant of "MyDoom.A." Microsoft, based in Redmond, Wash., and SCO have offered a total of $500,000 for information about the virus' creators.