A google search for MYSEARCH (MYWEB) leads to http://www.securemost.com/articles/trou_3_remove_mysearch.htm (and a lot of other sites). But it's from 2008, so might be outdated. In that case, visit our http://forums.cnet.com/spyware-viruses-security-forum/ for more recent info and be sure to tell all relevant details. For example, the exact name of that spy and the browser(s) in which it turns up.

I don't think, however, it comes from Microsoft. Why do you think so? I think you installed it yourself from some other source (maybe unknowingly).