A software vendor that tried to drum up sales by offering to clean up nonexistent computer spyware <A HREF="http://news.zdnet.com/2110-1009_22-5616035.html?tag=zdnn.alert">has been temporarily shut down,</A> U.S. regulators said on Friday. The makers of Spyware Assassin tried to scare consumers into buying software through pop-up ads and e-mail that warned their computers had been infected with malicious monitoring software, the Federal Trade Commission said.